The Runaway Friend: A Kirsten Mystery (American Girl Mysteries)

Kirsten Larson has been living on the Minnesota frontier for only a few weeks when her neighbor and friend, Erik Sandahl, disappears. Erik had promised to help the Larsons at harvest time--and he owes Uncle Olav money. Has Erik run out on his promises? Everyone seems to think so--except Kirsten. Can she figure out what's happened to her friend?

Takes place in 1854.