(The episode begins with Mordecai and Rigby playing football in the living room.)

Rigby: (Laughing) Dude! I'm open, I'm open, dude!

Mordecai: (Snickers) Go long, dude!

(Throws a ball of socks at Rigby, sending him backwards off the couch.)

Rigby: Touchdown, sock faces!

(He throws down the socks and starts imitating cheering. Right then, Benson enters.)

Benson: Hey, you two! Quit fooling around; we're having an emergency meeting.

Mordecai: Aw, what?

Rigby: Boooo.

Benson: (Signals to the door) Outside, now!

(He leaves as Mordecai and Rigby watch. A Clock transition to outside Skips's place occur. All the park workers are standing outside.)

Benson: Alright, everyone. I got some bad news. The park is being audited. (Points to Pops) Pops tried to pay the park taxes... (Gives him a look) ...with lollipops.

(The workers voice their displeasure.)
Pops: But I gave them more than enough.

Benson: We already went over this, Pops. You pay taxes with money, not lollipops.

Pops: (Sad) Oh.

Rigby: (Spits) What's the big deal? It's not like an audit is a bad thing.

Benson: It is a bad thing, Rigby. If we don't take care of this, the government takes our stuff away.

(The rest of the workers panic.)

Benson (continued): Okay, we only have till three to stop the audit.

(Slowly pan over to Muscle Man and Hi Five Ghost, who are thinking up something funny.)

Benson (continued): Does anyone know someone who can help us? Anybody? Anybody at all?

Muscle Man: (Raises hand) I know someone who can help.

Benson: If you say your mom, you're fired.

Muscle Man: (Long pause) MY MOM!

Benson: GET OUT!
Muscle Man: It was worth it!

(Muscle Man and Hi Five Ghost hi five and run off.)

Mordecai: (Thinks) Hmmm... Hmph. Hey! (Looks at Rigby) We know someone.

Rigby: We do?

(Mordecai raises his arms. Suddenly, Rigby knows who Mordecai is referring to.)

Rigby (continued): No! No way!

Benson: What? If you know somebody, you've got to tell me.

Mordecai: Rigby has a brother. (Rigby punches Mordecai.) And he's an accountant. (Rigby punches Mordecai rapidly.)

Rigby: Shut up!

Mordecai: Dude, what do you have against Don?

(Rigby gets mad, on the verge of crying. A ripple leads us to a flashback of Rigby's sixth birthday party. We pan down from the banner to a young Rigby.)

Young Rigby: Guys! Guys! Guys!

(Zoom out to reveal four bored children, one of them a young Mordecai)
Young Rigby (continued): Watch me blow out the candles, guys!

(A door opens. Rigby's younger brother, Don, stands in the doorway. Somehow, he is taller than Rigby.)

Young Don: Hey, Rigby. Happy birthday, bro.

(Rigby gets mad.)

Young Rigby: Wha? Wha? I told you to stay in the basement!

Young Don: Oh. Sorry, Rigby. I just wanted to give you some birthday sugar.

Young Rigby: I don't want your stupid sugar!

Rigby Friend 1: I'll give you some sugar, Don.

Rigby Friend 2: Yeah, me too.

(Everyone but Mordecai gets up out of their seats to hug Don. Then, Mordecai follows, but Rigby tries to stop him by grabbing his arm.)

Young Rigby: Don't you dare!

Young Mordecai: I'm just getting some sugar, dude. (Rigby lets go of him.) Besides, Don is cool.

(Mordecai goes to Don to give him sugar as everyone else laughs.)

Rigby Friend: You're the best, Don!

(Young Rigby growls as we ripple back to present day.)

Mordecai: Yeah. Don really made that party.

Benson: Call your brother!

Rigby: No!

Benson: Call your brother!

Rigby: No! I hate him!

Benson: Fine. (To Mordecai) Mordecai, you call him.

Rigby: You better not!

Mordecai: Dude, he could save the park!

Rigby: Dude, he could ruin my life! If he comes, I'm gonna tell him to leave!

Benson: (Walks up to Rigby) No, you won't! You be nice to your brother or you're FIRED! (To Mordecai) Call him. (He walks off.)

Mordecai: (Pats Rigby) Dude, just be cool until he stops the audit.

Rigby: Grrrr!

(Scene shows the park workers outside waiting for Don.)

Rigby: You guys are making a big mistake.

Benson: Don't ruin this for us, Rigby.

(We see Don drive up in his convertible.)

Benson: Really nice car.

Pops: He looks just like Rigby.

Don: (Gets out of his car) Did somebody order an accountant?

(Everybody laughs except Rigby.)

Benson: Thank you so much for coming on such short notice. I'm Benson.

Don: Benson. Give me some sugar. (Hugs Benson) Nice to meet you. Hey, who's this guy?

Pops: I'm Pops.

Don: Pops. Give me some sugar.

(Pops runs over laughing and gives Don a big hug.)

Don: Don. Good to meet ya.

(Don hugs Skips.)

Don: Look at this sugar shack. Come here, guy (Gives Mordecai a hug) I haven't seen you in forever.

Mordecai: (Chuckles) Yeah, I know! Oh, it's been forever.

Don: Rigby. Give me some sugar, bro.

Rigby: Don't you have taxis to do? Why don't you get to it?

Don: (Chuckles) Oh. He was always greedy with the sugar.

Rigby: Augh! I can't wait for you to get out of my life!

Don: What, bro?

Benson: (Angrily whispers to Rigby) You keep your mouth shut!

Rigby: (flinching) Nothing.

(The scene switches to Rigby in the hallway. Don and the others can be heard through a doorway in the computer room.)

Don: So then I said, "you're not an accountant, you're an account-can't!"

(The others laugh at the joke.)

Pops: I didn't realize accounting could be so fascinating!

Don: I'm just lucky I get do what I love.

Rigby: (Mocking Don) "Ohh, I'm just lucky I get to do what I love."

Don: (Turns around) Rigbone. Sugar?

Rigby: Shouldn't you be fixing the augite?

Don: You mean the audit?

Rigby: Don't correct me! I know what it is!

Don: (Laughing) Whoa, there. I'm sensing some tension, bro. I think it's time we all take a well-deserved break.

(The gang - minus Rigby - are outside, and they are playing football.)

Don: Mordo! Go long!

(He then throws the ball too far.)

Mordecai: I got it!

(He goes to find the ball and sees Rigby already holding it. A mad expression is evident on his face.)

Rigby: Hello, "Mordo". Enjoying your game?

Mordecai: Uh, sure, dude. Can you pass the ball?

(Rigby throws the ball hard at Mordecai's stomach.)

Mordecai: (Grunts) Rigby!

Rigby: He's not even doing the debit!

Mordecai: It's audit! (Sighs) Rigby, why don't you just try being nice to your brother? He's actually pretty cool.

Rigby: You don't get it! He...

Don: Hey, Mordo! We playing or what?

Mordecai: Uh, yeah, coming!

(Mordecai runs off, leaving Rigby looking just as angry as before.)

(Back inside, Don is alone at the computer.)

Don: Ah, I just about got this. With a few minutes to spare. (Rigby walks in.) Rigbone. How about a little pre-saving the park sugar? You know: for almost being done saving the park?

Rigby: NO!

Don: What's going on with us? You never give me some sugar. Did I do something?

Rigby: Yeah. You were born!

Don: Wow. That's heavy. I gotta get out of here.

(Don leaves the room.)

Mordecai: Dude? No, wait Don!

Don: I'm sorry. I just... gotta get out of here!

Mordecai: Dude, what are you doing? He was almost done!

Rigby: Ah, he's not so cool.

(Runs from the hallway to the computer.)

Rigby (continued): I can finish this up myself.

(Rigby presses a button on keyboard. A bunch of ads and warnings appear on screen as the computer beeps and rattles.)

Rigby: OK. (He presses another button and more ads pop up. The screen turns red and vibrates dangerously.) Augh! Mordecai! Help!

Mordecai: What did you do?

Rigby: I don't know!

Mordecai: This doesn't make any sense.

Rigby: No, no, no!

(Benson knocks on the door)

Benson: Don? We brought you a cake. It's almost three. Were you able to stop the audit?

Rigby: (Imitates Don, badly) Uh, almost done, Benson-bone. (Normal voice, to Mordecai) How do I send this thing?

Mordecai: No dude, call your brother back.

Rigby: No! I hate him!

(Rigby tries to push send on the keyboard, but Mordecai pushes him away. The two battle on the floor.)

Mordecai: Don't... Don't send it! Don't!

Rigby: Augh! Must... push... send!

(Rigby fights his way up to the keyboard and pushes send. The computer beeps quickly and the clock strikes. It shows a time of 3:05.)

Mordecai & Rigby: Crap!

Computer: You are late. Begin audit.

(The computer shows an 'AUDIT IN PROGRESS' status bar counting up. The computer shakes so much it causes the whole room to vibrate. The clock, lamp, and eventually half the furniture are engulfed in black and white binary code, which causes the items to disappear. The door also disappears, surprising Benson. The cake and Pops's hat are the next objects affected.)

Pops: Oh, my...

Benson: Where's Don? (Outside, Don is shown driving away, almost crying. The others run out after him.) Don! Wait! (To the others) What happened?

Mordecai: Rigby blew it! He wouldn't give Don sugar.

Benson: (Furious) What?! Go give him some sugar!

Rigby: (Even more furious) NEVER!

(Rigby runs away, panting. Inside, we see Mordecai and Rigby's room. It is slowly being eaten by the binary code. Mordecai enters.)

Mordecai: Rigby? Rigby! (He looks for Rigby and eventually sees his tail poking out from under a pile of clothes on his trampoline.) Rigby!

Rigby: (In a sad voice) Rigby's not here right now.

Mordecai: Quit being so selfish! (Moves clothing out of the way) The park is disappearing! We have to end this.

Rigby: Don't tell me what to do! You don't know what it's like to have a brother, so you don't know!

Mordecai: You're right. I don't have a brother. But I kinda know what it's like... 'cause I have you, dude. You're like my brother.

Rigby: (Climbing out from under a t-shirt) Really?

Mordecai: Yeah. You're to me like Don is to you. I think you're kinda awkward to look at, and you embarrass me all the time, and I wish I could trade you in for someone else. But I don't. Because you're like my brother. With brothers you always gotta make do. And I think you should make do, too.

(We see the binary code continuing to eat up the room.)

Mordecai (continued): Now will you please get Don to stop this audit?

(We see the exterior of Don's house, which is huge and modern. Mordecai and Rigby are talking to Don, who has answered his front door.)

Don: Look, I'm glad you guys stopped by but... I just can't finish the audit. I'm sorry.

(Don tries to go back inside, but Rigby grabs the door before he can close it)

Rigby: Don, please! I need your help with the audit, bro.

Don: Why is it so hard for you to give me sugar? (Almost crying) Why do you hate me?

Mordecai: He's mad about the birthday party.

Rigby: No! It wasn't just the birthday party. It's everything.

(He looks up at a photo of Don and Rigby, in which Rigby is literally in Don's shadow.)

Rigby (continued): I'm always in your shadow. You're so much better than me. Everyone likes you better, (Almost crying) and to top it all off, everyone thinks you're my older brother. I'm the older brother! Me! Why do all my friends think you're so much cooler than me?

(Don gasps and slaps his cheeks. A montage with sad music follows. He looks up at a photo of his younger self playing on a playground merry-go-round with Mordecai and Rigby's other friends, while Rigby sits alone on a seesaw. Then a three-legged race is shown, but Rigby isn't tied to anyone, so he remains alone at the starting line. Finally, Mordecai and Rigby are in a photo booth: Rigby looks angry as Mordecai beckons Don in as well. Photos are shown in which Mordecai and Don are front and center, and Rigby struggles to be seen at the back. The montage ends.)

Don: I... I had no idea. I'm sorry, bro. I didn't mean to steal your friends. I was just trying to be cool like you.

Rigby: Huh?

Don: I've always looked up to you, bro. I get my hair cut like you, I try to look like you, and I don't wear clothes, just like you. Remember when you started walking around naked? I thought you were so cool.

Mordecai: Yeah, dude. That was pretty cool.

(Don looks out the window and sees the park being engulfed by the binary code.)

Don: Alright. Let's go save your park.

(Don, Mordecai, and Rigby drive back to the park, which is being eaten to the point of oblivion by the audit. Inside, they see Pops, Skips and Benson hanging from the rapidly-disintegrating house.)

Don: Where's the computer?

(Mordecai points upstairs. Don runs up and sits at the desk.)

Don: Jeez! What did you do, bro?

Rigby: I tried to do the taxis!

Don: Hold on. This is gonna be close.

(Don works on the taxes as the others gather behind him. Sweat forms on his face and he bites his lip.)

Don: Alright, I got it! I just have to do one more thing.

Mordecai & Rigby: Do it!

(Some moments of silence follow and the workers look around.)

Rigby: Why isn't anything happening?

Don: Because... (Stands up and turns around, arms outstretched) I still need some sugar, bro.

Rigby: WHAT?

Everyone except Rigby: (Angrily) Rigby!

(As the music swells, Rigby, in slow-motion, jumps through space on the scattered household items to his brother, who catches him. The screen turns white and we see everyone outside, the house and park back to normal.)

Mordecai: Aw, Don. Do you have to leave already?

Don: Sorry, Mordo, but an accountant's work is never done.

Benson: Thanks for everything, Don.

Pops: Do come back soon!

Skips: Mmhmm.

Don: Well, big brother, if you ever need some sugar, you know who to call.

(Rigby smiles. Don gets in his car.)

Don: Later, gators.

(Don drives off)

Mordecai: (Leaning in to Rigby with a giant smirk on his face) Sugar?

Rigby: Shut up!

(We see Don's car - license plate reading SUGAR - driving into the sunset.)