Overview
Little Sister is a 1992 American comedy film written and directed by Jimmy Zeilinger. Starring Jonathan Silverman and Alyssa Milano, the film was released in the UK under the title Mister Sister.
Plot
Bobby graduates high school with his friend Mike. His father encourages him to forge his own identity and gives him a book of romantic poems. At college, Bobby and Mike join a fraternity where Bobby can be himself and not follow in his dad's footsteps. The fraternity leader tells Bobby to instruct his fellow pledges to be more like his father.
At a party, Bobby meets Sybil and fails to impress her with the poems. Bobby encourages Mike to stop taking his dad's advice and find a girlfriend. Bobby and Mike witness an argument between Diana and her boyfriend Derry because he does not care what she thinks. When she breaks up with Derry, Bobby asks her out, but she tells him off. Derry apologizes to Diana, and they get back together.
Bobby tries to woo Sybil again while trying to find a course to study. He ends up in an all-female classroom studying the sociology of women in history. He and Mike find out that they are enrolled in taxidermy class. Bobby, Mike, and their pledge brothers reminisce about The Brady Bunch for the fraternity leader. The leader wants them to steal a painting from the Zeta Alpha Zeta sorority house. After four failed attempts, Bobby pretends to be "Roberta" and fools the sorority sisters, though he is unable to get the painting. Bobby has difficulty maintaining both identities; he misses out on fraternity activities as himself but wants to keep the Roberta identity to be close to Diana.
From Wikipedia (CC BY-SA 4.0).