Harry the Homeless Puppy (Animal Stories #7) by Holly Webb

Grace can't have a dog of her own, but she loves walking the ones at the local animal shelter. 
Especially Harry - the cutest little Jack Russell puppy.

Harry looks forward to Grace's visits, and soon the two are best friends. But then Harry is rehomed. Grace knows she should be happy that Harry now has a home of his own, but she misses him terribly . . . and poor Horry doesn't understand at all.
Where has his beloved Grace gone?

(Illustrated by Sophy Williams)