Kitty has a secret: late one night, she overheard an unseen man describing a murder. And when she told the wrong person what she overheard, the killer began to focus on Kitty. Exploring the mountains and canyons of the Idaho back country with their friend Weevil while they look for tiger moths for Kitty's high-school senior project, Kitty and Gray begin to fall in love. Kitty's a self-described science girl. Gray writes songs, hoping to become a singer. Weevil, though wheelchair-bound, wants to become a music producer. Weevil and Gray realize that they have to keep Kitty safe. They know the killer is close, but they cannot discover his identity. At the same time, Gray's attorney cousin, Rylan, has met Kitty's teacher, Lina, hoping for a second chance at love.

At midnight, a star burns atop Aldape Ridge. Tiger moth pupae sleep in Kitty's family garage, waiting for spring. In a small stable, Gray sings his heart out. In the middle of a nasty divorce case, Rylan and Lina stand up for a small boy with uncaring parents. On Halloween night, the Headless Horseman rides again. And in the canyon to the north, a killer in a pickup waits for the right moment to strike.

Tiger Moth is a world rich with canyons and rivers, mountains and deserts, wildlife, skies bright with stars, many memorable characters, a brutal killer-and a tender love story.