"Brian" is the sixth episode of Season 2 of Teen Titans Go!, and the fifty-eighth episode overall. It first aired on 31 July 2014 on Cartoon Network.
The Titans and the Little Buddies throw a surprise party for Birdarang and Beat Box. When the Titans leave to check out a crime alert, Cyborg tells them to keep the party going while they're gone. Eight months later, the Titans still haven't returned and the party is still going.
Beat Box and Birdarang return to Titans Tower and are met with an empty and abandoned living room. The lights turn on to reveal a surprise birthday party for the two of them, consisting of the Teen Titans and several Little Buddies which includes Dave, Super Robin, and Painbot. Starfire and Cyborg congratulate the two little buddies and Raven prepares to say something until Robin interrupts with a speech he wrote for the occasion. However, he is attacked by Dave much to Raven's gratitude. When asked what he wants, Birdarang declares a beat which Beat Box supplies. As the celebrators begin dancing, a crime alert rings and Robin orders the Titans into action. As they leave, Cyborg tells the Little Buddies to keep the party going which they do for eight months.
During the eight months, the Titans were imprisoned by the Brain. Robin declares that he won't get away his scheme, but the villain simply remarks that he's nearly complete with his project. Beast Boy asks if they'll eat soon, but addresses the Brain as Brian, confusing the organ. He corrects him yet Beast Boy complains that it's not reading school and the Brain, frustrated, leaves. Robin informs the Titans that he's got another plan to escape, but Cyborg implores him to give up as every escape attempt has failed in the last eight months. Starfire adds on that they'll be tortured if they attempt another escape and Raven includes that the Brain stripped them of their powers. Robin counters that the Brain didn't take the powers of his brain, heart, or muscles and fills them in on his plan. Beast Boy will create a diversion, and when the Brain arrives to check on him, Robin will attack and defeat the villain. Cyborg and Raven claim the plan will never work as Starfire implores Robin to not let Beast Boy go through with his plan, but Robin commands the green shapeshifter to do so and he accepts. Beast Boy claims to need a doctor and faints, but the Brain easily sees through their deception. Beast Boy pleads for him not to torture them, but the organ rolls into a button and electrocutes the Titans. As they recover, Robin reveals another plan which is met by groans from the others.
Back at Titans Tower, the Little Buddies are still partying when Super Robin notices an alert regarding the Titans' capture. He swings Bidarang to him with the grappling hook and makes him translate his gestures. Birdarang reveals that he mistook the alert as a party light and volunteers to embark on a suicide mission to rescue the Titans. Dave, Beat Box, and Painbot volunteer as the well and five suit up in order to successfully complete their mission. Through the aid of his grappling hook, Super Robin reaches the roof of the Brain's HQ and stealthily maneuvers until noticing that the other Little Buddies have been dancing to a track played by Painbot. After turning off the music, they are confronted by Monsieur Mallah. Super Robin manages to knock him back, but he is distracted by Birdarang and punched by the gorilla. He proceeds to trap them in a capsule which Birdarang labels as a party foul.
Inside the Brain's HQ, Robin successfully removes the control panel's covering and attempts to disconnect the wiring. Cyborg tells him to give up as Beast Boy notes that he's fine with being imprisoned due to having a bucket and receiving three meals a day. Raven agrees with Beast Boy by saying it's quiet while Starfire looks forward to tomorrow night's grilled cheese. Robin's hand is caught between two steel blades and he begins screaming in pain. The other Titans plead for him to scream quieter as to not draw attention to the Brain, but the villain notices and electrocutes them once more. Meanwhile, Monsieur Mallah is transporting the contained Little Buddies across the headquarters. Birdarang convinces them to not give up by using Paintbot as a success story on the Titans' treatment toward them although Painbot still feels the need to cause pain. The Little Buddies, motivated, break out of the capsule and overpower Mallah. In order to cause a distraction, Beat Box plays a beat for the guards and, while they're dancing, are electrocuted by Painbot.
While the other Titans are playing with cards, Robin begins using a spoon to dig a tunnel to use as an escape route yet they are content with staying here as the Brain had promised them a TV if they behave. Robin orders them to dig as no one will be rescuing them yet Birdarang arrives and informs the Titans that they're throwing them a surprise rescue party. The other Titans attempt to tell Robin, but he insists on completing the tunnel. Outside, the Brain halts the Little Buddies' escape attempt and transfers his brain into a robotic suit filled with the Titans' powers known as Project B.R.I.A.N.. Beast Boy corrects the Brain on his spelling and the villain berates himself for not realizing the mistake earlier. He charges and Birdarang calls the Little Buddies into action.
Dave activates a metallic wolf head in an attempt to crunch the Brain, but he is effortlessly tossed aside by the supercharged villain. Painbot dodges Dave and shoots CDs at the organ, but he activates a sword which he uses to deflect back at the robot, knocking him back. Super Robin skillfully jumps from disc to disc and attacks the Brain's capsule with his wings, but he is picked up and thrown aside. The Brain notices Beat Box and Birdarang dancing and shoots a sonic blast at Birdarang, but Beat Box jumps in the way at the last second. Birdarang pleads for Beat Box to stay with him, but the little buddy ultimately dies. As he mourns for Beat Box, the Brain prepares to destroy Birdarang, but the little buddy expands into an android. The Brain shoots a raven by using Raven's powers, but it is zapped apart by Birdarang. The organ unleashes a barrage of star blasts at the little buddy, but he skillfully avoids the attacks and takes shelter behind a pillar, but one of the robotic suit's hands transforms into a snake and coils Birdarang.
Birdarang twirls and destroys the hand before landing and throwing his head like a boomerang, effectively cutting off the robot's power supplies before kicking the Brain's capsule out of the robotic body. Raven, Starfire, Beast Boy, and Cyborg's powers return to them and the latter uses a sonic blast to destroy the cell they were trapped in. Cyborg approaches Beat Box and replaces the stereo's batteries with his own, but he is still unable to be revived. Upon further inspection, Cyborg spots a battery facing the wrong way and fixes it, effectively activating a beat that the Titans and Little Buddies dance to. In the cell, an oblivious Robin continues digging, certain that the tunnel is their only hope.