"Indecent Porpoisal" is the twenty-first episode of Season 4.
Synopsis[]
With Winter Lake finally able to afford to have prom on the Odyssey again, the students and faculty are eager and excited to return to tradition. However, a "current events" assignment in the senior 20th/21st Century History class awakens Victoria to the presence of a pod of porpoises that has been decimated by reckless cruise ship captains. Despite being prom-crazy in the past, she decides to boycott the dance since it's too late to change the venue. When Hassan joins her cause, protesting down on the docks instead of dropping it like it's hot on the deck of the boat, she wonders if he's committed to the cause or if he has ulterior 18-year-old-boy motives. Meanwhile, Vera discusses Bailey's future at Winter Lake with her advisor, gossip about Leo and Maya gets out and they drive themselves up a wall looking for the source, and Mira kills it on the dance floor.