In the spirit of her 1996 best-seller ”Where the Heart Is,” Letts delivers a tender yarn of finding one’s identity in a rural Oklahoma replete with single mothers, eccentric townsfolk, and multiple Wal-Mart references. A man arrives in the sleepy town of DeClare looking for the woman who put him up for adoption. The stranger turns out to be Nicky Jack, the baby boy who went missing after his mother was brutally murdered nearly 30 years prior. Suddenly, DeClare stirs with reawakened memories of an unsolved mystery. Though the unfolding whodunit never quite meshes with Nicky Jack’s journey of self-discovery, Letts writes with such earnestness and local color that you don’t mind extending your stay to see how it all turns out.