Hard-boiled Trish Winterbottom is on the verge of having her new champion Bedlington terrier put down; glaucoma has left him blind and useless for showing. But her daughter's love-starved best friend Cory, 13, has a better idea: she'll adopt Sterling and at least ""give him a happy life."" Cory enjoys going with the Winterbottoms to dog shows, though she dislikes the cutthroat competition; now she learns of one event, as yet unrecognized by the AKC, in which Sterling may compete: ""agility,"" which draws a nicer, more laid-back crowd. For a year, Cory devotes herself to tenderly training Sterling to maneuver an obstacle course of jumps, tunnels, and swaying bridges in response to voice commands; his fourth-place ribbon is a triumph for both. The authentic doggy details--complete with a rough-diamond groomer who provides moral support and a chance to earn money for supplies--dominate the narrative here; a co-plot concerning the emotional rehabilitation of Cory's family, withdrawn and alienated since her little sister's death from cystic fibrosis, is developed schematically rather than in depth. Sterling's sudden, painful death in the end seems contrived to give Cory a needed insight: her mother had not so much abandoned her as grieved ""for the loss of the little girl to whom [she] had been the world."" The prolific Hall knows her craft, but this is not among her best; still, a good addition where dog stories are popular.