Radiance by Alyson Noel (author) (UK edition)

Riley Bloom died, aged twelve, in a car crash with her parents and her beloved dog Buttercup. Her sister Ever survived – but that’s another story. Riley must let go of Ever and all the things that tied her to life – and discover what she’s meant to be in the afterlife. Riley is a soul catcher. That means helping the unhappy lost souls who stick around in the human realm to move on – and find their own place, over the bridge, in the great hereafter. With her spirit guide, Bodhi, and Buttercup by her side, Riley embarks on an adventure that will take her around the world – sending ghosts back where they belong, until she can finally make it there herself.