Calvin calls a meeting of G.R.O.S.S. to order. President and First Tiger Hobbes gives an attendance report. Club Secretary General Hobbes gives the minutes. Calvin then calls for a field report from Top Scout Calvin. Hobbes says you can tell this is a great club because they have so many officers.

Top Scout Calvin reports the enemy has been sighted on the sidewalk two doors down. It's Susie Derkins, an acknowledged girl. Calvin recommends they establish a strike force to bug Susie. Hobbes calls for volunteers.

As they climb down from their tree fort, Calvin says he'll be the strike force commander, while Hobbes is the special agent in charge of munitions. Calvin suggests filling a water balloon and sneaking up on Susie through the back yard. Hobbes wants to be official cartographer, mapping their hiding places and escape routes. Calvin decides to be the code expert and make an unbreakable code. Hobbes runs to get paper. As they both work on their tasks, Calvin says he hopes Susie doesn't go anyplace for a while.

Calvin has finished the secret code. He has assigned each letter a totally random number. For instance, for the letter "A", you write 3,004,572,688. Hobbes admits that's a good code. Calvin says they only have to commit it to memory. He asks if Hobbes has finished the map of their neighborhood. Hobbes isn't quite done yet. He asks how many bricks there are on the front walk.

They have their map, the code, and a water balloon. They're ready to soak Susie. Hobbes says they should run to the big tree out back, then to the bush out front, then the ditch out back, then the tree out front. He explains to a winded Calvin that's to lose anyone who might be tailing them. Calvin is going to write Hobbes a note in code. He asks how to spell "nincompoop".

They made it to Susie's yard, but she's not there. Calvin is distraught that all their plans have gone for naught. Hobbes suggests she might have only gone in for lunch. Her toys are still left out, so she's probably planning to come back. Calvin's eyes bulge, and he wrings his hands. He says that gives him a fabulous idea.

Hobbes asks what Calvin is doing. He's picked up Susie's doll. Hobbes says they can't take it. That would be stealing. Hobbes asks if they're going to give it back. Calvin replies they will if she pays the ransom.

Susie comes back and wonders what happened to her Binky Betsy. She knows she left her there, and she wonders if someone took her. Everything else is still there. Calvin and Hobbes are making a ransom note. Hobbes says he likes cut-and-paste. Calvin asks how much they should ask for. He thinks one hundred dollars.

Susie goes back inside telling her Mom that she can't find her doll. The doorbell rings. No one is there, but there is a note on the ground. Susie reads the note. It reads "Susie, if you want to see your doll again, leave $100 in this envelope by the tree out front". It warns her not to call the police. It says she can't trace or find them. It's signed "Sincerely, Calvin".

Susie is outraged to receive a ransom note. She crumples the note and says he can't get away with this. She notices something else in the envelope. It's a picture of Binky Betsy tied to a chair. Susie is horrified. In their tree fort, Calvin tells Hobbes this is a great club. Hobbes asks Calvin what he's going to do with his $50.

Calvin suggests walking real casually down the sidewalk to see if Susie put the hundred dollars by the tree. They march along with Calvin saying he enjoys his afternoon constitutional. Hobbes says it's quite invigorating. They see the envelope. Calvin figures they're rich. Hobbes says they should sneak up and get it. Susie is hiding behind the tree.

Calvin sets Hobbes down and tells him to watch for Susie while he counts the money to make sure it's all there. Calvin opens the envelope to find no money. There is a note. Calvin reads "now we're even". He wonders what that means. Susie has grabbed Hobbes and run off. Calvin notices Hobbes missing.

Calvin chases Susie, who's carrying Hobbes. Calvin tells Hobbes to bite her. Susie reaches her home and closes the door. From an upstairs window, Susie yells down for him to get away from their door with that drill.

Calvin is fuming about Susie. Calvin said he kidnapped her doll, but that's no reason to retaliate. He says girls have no sense of humor. He storms off saying this was all funny until she did the same thing to him.

Calvin brings Susie's doll back to her house. Susie opens the door and tells Calvin she thinks she might rather have his tiger than her doll. She tells Calvin he can keep Binky Betsy. Calvin doesn't want a doll. Susie says he'll grow to like her. She has the cutest accessories you can buy. Calvin says he wants Hobbes. Susie tells him she thinks Hobbes likes it better there with her. Calvin yells that he does not.

Calvin offers to give Susie her doll and a quarter to return Hobbes. Susie agrees and tells Calvin to leave her stuff alone next time. They exchange and think each other are jerks. Later, Calvin asks Hobbes what kind of tiger he is. He didn't try to maul her. He asks what he was doing in Susie's house. Hobbes says wouldn't Calvin like to know.

In their tree fort, Calvin says it doesn't give their club a lot of credit when the First Tiger is a willing captive of the enemy. Hobbes sticks out his tongue. Calvin says they stole her doll, and he had to pay ransom. He says it's a disgrace. Calvin doles out demerits for besmirching the club's reputation and conduct unbecoming an officer. He also gives a censure for not devouring Susie when he had the chance. When Calvin asks if there's anything else, Hobbes tells him he almost gave her their code when she rubbed his tummy. Calvin asks whose side he's on.

Calvin declares this a sad chapter in G.R.O.S.S. history. Hobbes says he did some spying after gaining Susie's confidence. He says he read an open page of Susie's diary. Excited that Hobbes intercepted a secret message deep in enemy territory, he asks what it said. Hobbes tells him "Calvin is a pig-faced smelly fat-head". Calvin says their club is a success. He welcomes Hobbes back and offers promotions for everyone.