Timmy in Trouble by Holly Webb
Katie can't believe it when her parents agree that she can have a puppy. And when she sees the lively Timmy, she's sure her family will fall in love with him, just as she has. But her sister Jess is worried about how Misty the cat with react to the new arrival. Katie thinks they'll get used to each other, but things don't go as planned. Every time Timmy tries to play with Misty he upsets her and gets into trouble. Timmy is so sad. Why doesn't Misty want to be friends?