Calvin tells Mom he doesn't feel so good. Mom agrees that he doesn't look good. She feels his forehead. Calvin says summer vacation started, and he can't be sick. Mom tells him she's going to get the thermometer. Calvin yells out that he refuses and that he hates thermometers. Mom puts one in his mouth. Calvin doesn't believe her when she says it takes two hours to register. Mom tells him to be nice and quiet, and she'll check on him in the afternoon.

Calvin is scratching himself. He says it's worse than bug bites. As he keeps scratching, he says whatever it is drives him crazy. He pulls off his shirt and sees spots. Calvin thinks that's cool.

The doctor tells Mom that Calvin has chicken pox. Calvin asks if he's a veterinarian. The doctor says it will run its course in about a week. Calvin complains that the doctor is mad. He accuses him of having the real doctor tied up and gagged in the other exam room. The doctor says Calvin is extremely contagious, so he needs to be kept from other kids. Calvin wants Mom to sue him and drive up his malpractice insurance. Horrified, Mom repeats that Calvin has to be inside for a week. The doctor notices a nasty twitch Mom has developed. Calvin offers, for ten dollars, to make sure the doctor sees all the kids in the waiting room again real soon.

Calvin calls Susie on the phone. He asks her if she'd like to come over and play. Susie says he's never invited her before. In the background, Mom asks Calvin what he's doing. He tells her to go away. Mom says he's contagious and can't have anyone over to play. Calvin says she's spoiling the whole thing. He was trying to trick Susie into catching his bug. The phone hangs up. Susie calls to her Dad to see if there's any chance of him transferring.

Hobbes asks if Calvin is absolutely positive tigers can't catch chicken pox. Calvin says yes. Hobbes isn't so sure, so he shows his claws to Calvin. Calvin wakes Mom up to ask if she's absolutely positive tigers can't catch chicken pox.

Calvin shows Mom his chicken pox are going away. He tells Mom to remember that this week doesn't count. Mom asks what he means. He says summer vacation days don't count if you're sick. So he gets to go to school a week later to get his full allotment of vacation. Calvin and Hobbes are looking at a book. Calvin asks what the next amendments says. He knows it's in there someplace.