Tamsyn Lyman's day can't get any worse—or can it? It would seem so when her car breaks down along the interstate during a thunderstorm with her grandmother's dead cat Guido inside. Thankfully, middle-aged tow truck driver Daniel Stevens is there to assist.

In the rain, both Tamsyn and Daniel are struck by another vehicle. Instead of waking up in the hospital—or worse, not waking up at all—they find themselves on the alien planet of Eidolon, both of them young, healthy, and alive, including Guido. Only Tamsyn's sapphire necklace, a gift from her grandmother, remains to remind them of Earth and home.

On this new planet, these confused explorers must evolve quickly to survive. They meet strange creatures and discover that it was the mysterious Heart of Eidolon that beckoned them there. Tamsyn and Daniel represent some sort of change, but what does this far-off planet need, and will these novice space explorers ever get home?