That Bitch is a storyline mission in Chapter 1.
Jimmy wanders into the Girls' Dorm to overhear an argument between Beatrice and Mandy. Mandy has stolen Beatrice's lab notes, and easily pushes her around when Beatrice tries to take them back. With no one else around, Beatrice begs for Jimmy's help. When her offer of giving him a kiss doesn't appeal to him, she threatens to tell the whole school that he's a sad sicko who likes to spy on girls changing in their dorm. Jimmy agrees to get the notes back.
Jimmy meets Gary beside the Girl's Dorm and tells him about his plan, and Gary suggests him to leave a stink bomb in Mandy's locker. Jimmy heads to The Library, where he finds Fatty playing Grottos and Gremlins. Jimmy can either buy a stink bomb or bully him for one. He can also pick up stink bombs that spawn around the school or make some with his chemical set if he has already passed Chemistry 2.
Jimmy arrives in the girls locker room under the Gym. Pinky, who was in the locker room, screams and runs to get the prefect Seth Kolbe. Seth goes to investigate, forcing Jimmy to hide. Once he's gone, Jimmy picks the lock to Mandy's locker and throws the stink bomb in. Mandy shows up and opens her locker. The stink bomb goes off, causing Mandy to run to the toilets to vomit.
Taking the lab notes back to Beatrice, Jimmy is rewarded with a kiss and her affection.
If Jimmy has stink bombs in his inventory when he starts the mission, he skips the meetup with Gary and exchange with Fatty, heading straight for the gym instead.
Defend Bucky and That Bitch are unlocked at the same time, when Save Algie is completed. They must both be completed in order to unlock the next mission, The Candidate, and the side mission The Diary.
- Once this mission becomes available, Beatrice and Mandy will not appear in Free Roam again until this mission gets completed.
- If Jimmy doesn't have any stink bombs and has to talk to Gary, Gary will be found wandering around once the cutscene ends. This is one of the few times he can be interacted with in free roam. Beating Gary up won't fail the mission.
- Instead of buying or bullying Fatty for Stink Bombs, originally Fatty agreed to give Jimmy stink bombs if Jimmy got him a box of chocolates from Edna. There are unused audio files for this segment from Jimmy, Fatty, and Edna, respectively.
- Hitting Mandy with any weapons while she is throwing up will have no effect, although she will make the same sound effect as anyone else who gets hit with a weapon.
- Mandy's throwing up voice is not part of the "speech audio" but instead mixed with "effect audio".
- If Jimmy leaves and re-enters the gym after collecting the notes and goes back to the girl's locker room, Mandy will be standing in the stall in idle mode. The player won't be able to interact with her and attacking her will have no effect.