When a new family moves into the property next to the Weston farm, suddenly Jo and her beloved dog Billie have a new best friend and netball buddy, Ava. But strange things are happening in Tamar Valley. Farm gates are left open, Jo's escape-artist cow Moo-dini is on the loose, mountain bikers are going missing and then Billie disappears! Jo and Ava will have to use all their wits to solve the mysteries.