The disappearance of brian hits quahog hard. This is not the only misfortune though, Lois cannot find Stewie anywhere either! Meanwhile, while everybosy sits around questioning there where abouts, Brian and Stewie visit the local Quahog bank so that Brian can deposit holiday money in his safe deposit box. Stewie then wants to go to a store to return a $3,000 Thom Browne sweater. While they are still inside the vault, the door closes at the end of the work day and locks them inside until the next morning. Frightened, Stewie soils his diaper. Worried he will get a rash from the dirty diaper, Stewie desperately tries to make Brian eat his feces by threatening him with a gun that Brian had stored in his deposit box. They discover that Stewie has a cellphone in his pocket, but there's only enough charge in the battery for one short phone call. Unfortunately, Stewie uses the last of the phone's battery charge to call the clothing store rather than for help. Enraged, Brian strikes Stewie, throws his phone on the ground (thus damaging the phone), and yells at Stewie, making him cry. Instantly remorseful and wanting to repair his relationship with Stewie, Brian reluctantly agrees to eat Stewie's feces in order to provide him with a clean diaper and make up for making Stewie cry. While watching Brian eating, Stewie becomes nauseated and throws up; Stewie then convinces Brian to eat the vomit. Realizing that he has nothing to clean his bottom with, Stewie manages to convince Brian to clean his bottom with his tongue in order to avoid infection, much to Stewie's pleasure. Afterward, they both decide to take a nap, but soon they realize that the next day is Sunday, meaning that they will have to wait another day before they can be released from the vault. Awaking from his nap, Brian decides to drink a bottle of scotch that he had stored in his safety deposit box. He offers Stewie a sip, and they both become so drunk that Brian agrees to pierce Stewie's ear with a pin from his sweater, leaving Stewie with a bloody ear for the rest of the episode. Stewie and Brian discuss The Dog Whispererand Cesar Millan, and Brian explains that he is inspired by the philosophy about dogs' instinctive ability to live in the present and with purpose. Stewie, however, points out that Brian himself does not appear to live with any specific purpose. Angered at the implication, Brian begins insulting Stewie, who bitterly retaliates by revealing that he could have gone all day without having his diaper changed, and only thinks of Brian as a passing amusement. Stewie dares Brian to shoot him with the revolver in the deposit, which Brian earlier said to be bullet-free. It is revealed that Brian lied, and he attempts to shoot Stewie. The two then find a security camera hanging on a wall of the vault. Brian tries to use it to call for help, but Stewie points out if there was someone out there, they would have been saved. Brian then realizes that the camera has recorded him cleaning Stewie, which amuses the infant, but Brian is upset about gaining a laughingstock reputation. Stewie then prematurely causes the gun to discharge, causing the bullet to randomly ricochet off the vault walls, smashing Stewie's already-broken phone and the bottle of Scotch, and forcing the two under the table. Soon after sobering up, Stewie stretches and takes out a Jenny Craig Anytime Bar from his shopping bag. Brian loses his temper with Stewie for not revealing that he had been storing food the entire time. After Brian calms down, Stewie asks him why he had the gun in the first place, eventually coaxing Brian into revealing that he keeps the gun in case he ever wants to commit suicide. Brian confesses that he cannot find his purpose in life, and finds comfort in knowing he has the option of killing himself. He admits that the Scotch was to be a last drink. Stunned, Stewie admits that he would be lost without Brian, claiming he is the only person in the world that he really cares about, and he eventually confesses that he loves him as an irreplaceable friend, and that he gives his life meaning. Brian tells Stewie he loves him back. In addition, Stewie reminds Brian that maybe making someone else happy is enough, because it is the best gift one person can give, for which Brian thanks him. Stewie falls asleep as Brian reads the beginning of David Copperfield to him. The following morning, the vault door opens, and Brian carries a sleeping Stewie and their belongings out of the room in silence.