Calvin gets a valentine in the mailbox. It's from Susie Derkins. Calvin reads the card, which says "Be my valentine". Hobbes starts making fun of Calvin. He starts singing "Calvin and Susie, sitting in a tree, K-I-S-S-I-N-G". Calvin says he's not her valentine just because he got that in the mail. He asks if the Postmaster General knows about this. Hobbes continues ridiculing Calvin by singing "First comes love, then comes marriage, then comes baby in a baby carriage". Calvin is horrified to think he has to kiss Susie if they're valentines. Calvin wants a lawyer. He says she can't make him her valentine. Hobbes sees Susie coming. Susie says hi to Calvin, who throws the valentine on the ground. He tells her to get away from him, and he's not her valentine. He tells her to take her card back. Susie tells Calvin the card wasn't for him. She asks if he read the back of the envelope. When Calvin looks at it, it reads "Calvin, please give this to Hobbes". Calvin is shocked! Hobbes, with a smile on his face, says "Hot Dog! Smooch City, here I come".