Calvin sees Mom with her hair wrapped in a towel. He says since she showered now, she and Dad must be going out. He also notices that he wasn't asked to clean up, so that means he's staying home. Since he's staying home, that means Mom has gotten a baby sitter. With a gasp, he realizes that means Mom probably hired Rosalyn! Mom confirms his fears by saying "Brilliant, Holmes". Calvin yells in horror.

Calvin runs to his bedroom warning Hobbes that they have to hide since Rosalyn is coming. Hobbes says they're usually in bed by 6:30. Calvin adds they get no TV, no horsing around. She walks in and sends them straight to bed. Hobbes complains she doesn't even give them a good night kiss. Calvin makes a face and asks if he would really want her to.

Calvin asks Dad where they're going that night. He wonders why he and Hobbes can't come along. Dad says they're going to dinner and a movie to get some time by themselves. Calvin says that he could come. Hobbes wouldn't kill anyone. Calvin asks why they can't come, why aren't they wanted around. He asks if the movie's dirty or something. Dad tells Mom that they'll have a dinner with real pauses in the conversation. Can she imagine?

Mom lets Rosalyn in. She tells Rosalyn that Calvin is upstairs hiding from her, so she may have an easy evening. Rosalyn says that would be good, since she has to study for a big test tomorrow. Upstairs, Calvin and Hobbes are listening around the corner. As Hobbes rubs his paws together, and Calvin puts on an evil smile, he declares that tonight is "The Revenge of the Baby Sat".

Rosalyn is studying her papers at the table. Calvin comes up and asks what she's doing. She tells him she has to study tonight, so she wants it quiet. Calvin says he understands and tells her he and Hobbes won't make a peep. He asks to see what she's studying. As Rosalyn tells him not to touch anything, Calvin grabs her notes and runs away.

Rosalyn chases Calvin, who has her study notes. Calvin and Hobbes run into the bathroom. They lock the door just before Rosalyn gets there. She tells Calvin through the bathroom door that if he doesn't open the door, his parents will never find his remains. Calvin holds her papers over the open toilet and tells her "Here go your notes".

Rosalyn pounds on the bathroom door telling Calvin he has two seconds to unlock the door and return her science notes. Calvin suggests she adopt a more humble attitude. He warns her she wouldn't want anything to happen to the notes. Rosalyn rattles the door knob, calls Calvin a "Scummy little troll". As she's telling him what she'll do when Calvin's parents get home, she hears the toilet flush. Calvin tells her "There's one page". Rosalyn is horrified.

Rosalyn grits her teeth and says Calvin had better not really have flushed her notes. She has a test tomorrow. Calvin says with that at stake, his demands should seem reasonable. Rosalyn says he doesn't get any demands. She wants him to open the door. As Calvin walks over to the toilet, he says a high school senior should catch on quicker. He says he should write the school board. Hobbes readies the "torpedo tube".

Calvin tells her he hopes she memorized the page already, because she'll never see it again. She tells him not to flush it and asks what his demands are. Calvin tells her he wants to stay up until his parents drive in. Then, he wants Rosalyn to get a pizza and rent a video player. She tells him he's out of his mind. Calvin continues and asks if she's writing these down.

Hobbes doesn't hear Rosalyn any more. Calvin calls out to her. No answer. Calvin wonders if she went away. Hobbes says they still have her notes. Calvin can't figure out what she's doing. Hobbes wonders if she's calling the fire department to open the door with an axe. Calvin thinks that would be great. He hopes they bring their biggest truck. Hobbes hopes Mom and Dad are having a restful evening.

Calvin opens the bathroom door and peeks out. He calls to Rosalyn, asking if she's calling the fire department. She darts around the corner and grabs Calvin. As she carries him off, he tells her he didn't really flush her notes. He says they're all there and asks her not to kill him. He's put to bed. Hobbes points out it's 7:00. They got to stay up a half hour longer than usual.

Mom and Dad return home. Mom asks if Rosalyn had a quiet evening and got her studying done. Rosalyn has a worn look to her face. She says she's sorry, but tonight is going to cost them. Having paid Rosalyn, and her having left, Dad asks Mom if she's sure that no one in town will baby-sit Calvin. Mom replies that maybe he'd like to spend a week on the phone.