A.P. Bio Season 1 Episode 9 Rosemary's Boyfriend

Jack Griffin, a disgraced Harvard philosophy professor working as an Advanced Placement (AP) biology teacher at Whitlock High School in Toledo, Ohio, attempts to sabotage a biology presentation by Miles Leonard, the school's performing arts teacher. Jack's plan is foiled, however, by Principal Durbin, who appoints Miles as the school's new drama director and tasks Jack with creating a new acid rain-themed project for his students.

Meanwhile, Jack becomes obsessed with learning the identity of his ex-girlfriend's new boyfriend, who he believes to be her boss at an accounting firm. He enlists the help of his students to stake out the firm and gather information, leading to a humorous sequence of events involving mistaken identity and a stolen briefcase.

As the acid rain project approaches, Jack struggles to come up with a cohesive plan, leading him to recruit fellow teacher Mary Wagner, who he believes to be an expert on the topic. Their collaboration leads to some unexpected breakthroughs, and the project ultimately impresses Principal Durbin and the school board.

The episode also delves into the personal lives of some of the supporting characters, including Durbin's unsuccessful attempts at online dating and the romantic tension between science teacher Stef Duncan and gym coach Marcus Kasperak.

Overall, "Rosemary's Boyfriend" is a comedic and character-driven episode of A.P. Bio that continues to develop the show's cast while also delivering plenty of laughs.