Tommy knows the rules. Stay off the logs on the beach. Walk near the water but don't get your feet wet. If the sick try to get you, don't stop to think, just drop, roll, and run away fast. Tommy's still alive because he followed the rules. Then he meets Jessie, a girl who doesn't believe in rules, not even the most important rule of all: tell people if you're sick.
Includes BONUS story "Patient Z.