Some routes are easier to run than to finish.

At seventeen, Pim is one of the best canal runners in Copperwhistle—fast, reliable, invisible. She's spent nine years building a reputation on one simple rule: trust no one, need no one. It's kept her safe. It's kept her alone.

Now she's aging out of the only life she knows.

When a message she delivered goes missing, Pim's reputation—her only currency—is suddenly worthless. Someone is intercepting deliveries from the runner network, and the suspicion is falling on the runners. To clear her name, she'll need to do the one thing she's sworn never to do: ask for help.

The investigation pulls her into an unlikely partnership with Tenny, a former runner who's already made the leap Pim fears. It forces her to see the people who've been quietly looking out for her all along—the baker who always has extra bread, the old runner on his bench who sees too much, the runmaster who's been watching her for nine years without ever asking for thanks.

The mystery has an answer. The harder question is whether Pim can stop running long enough to find it.