Zak is Hannah's two-year-old brother from the Holly Webb book Oscar's Lonely Christmas.
Oscar's Lonely Christmas[]
Zak comes calling to Hannah telling her that their mum wants her, and it turns out that they are getting a Dalmatian puppy. The next day, the family goes to Dashing Dalmatians and greet Lisa, who runs the place. They meet Bella and Robby, the two adult dalmatians, too. Hannah and Zak go and see Chrissie, another dog, and her puppies. Hannah picks one and names it Oscar.
When the family brings Oscar home, Zak scares him by squealing excitedly and flopping down on his cushion, but Mum picks him up and he starts crying. Hannah is cross with Zak for scaring Oscar, but Mum and Dad let him get away with it. One day, Hannah comes down the stairs and finds Zak holding Oscar near the stairs. She furiously tells him not to bring him upstairs and to let him go, but Zak won't. Mum catches them both and blames Hannah for bringing Oscar upstairs and upsetting Zak. Hannah is cross with Zak, and then decides to keep an eye on him to make him leave Oscar alone.
One day, Zak finds Oscar and hugs him too tight. Oscar growls to save himself and Zak lets go of him in fright. When Hannah comes home and finds Oscar hiding under the stairs, Zak tells them that Oscar growled and doesn't add that he hugged Oscar too tight, and Hannah tries to tell Mum and Dad that Zak has been bothering Oscar, but Mum and Dad let him get away with it, though Dad tells Zak to be gentle with Oscar.
When Hannah finds out that her angel wings for her school nativity play are torn, she thinks Zak has done it and angrily yells at him, but Mum says it is Oscar. Hannah doesn't believe her at first, but when she finds white bits in Oscar's mouth, she realises that Mum is right, but marches out of the living room without even saying sorry to Zak. The next day, when she comes home from school after her play, Gran has told her that Zak has fallen off the climbing frame at nursery and been taken into hospital with a stitched head. Dad tells her the full news, exhausted, and apologizes for not coming to see the play. When Hannah comes home from school to find Zak lying on the sofa with a bandaged head the next day, she sits next to him and strokes Oscar's ear with him all evening.
On Christmas Day, when Mum goes to the hall when she hears Zak crying, Hannah decides to take Oscar out for a walk. When they did, and she and her family are reunited with Oscar's help for leading the way home, she invites Zak to give Oscar a piece of turkey, and the siblings watch a happy and full Oscar sleep peacefully on his cushion.