Just after his tenth birthday, the last thing Zak expects to hear is that his mum is having a baby and he has to give up his room for an ageing old grandmother who is coming to live with them! With the help of his friends and a series of cheeky pranks, Zak is convinced it'll be no time before he can reclaim his rightful territory! But Zak soon discovers that his nani is no ordinary old grandma but a former chess prodigy, able to outwit and outdo him - and his friends - at every turn. Just as both players begin to forge a mutual respect and a friendship that might finally overcome all obstacles, Zak begins to notice things. Like how Nani sometimes forgets where she is...

Or who Zak is... In a desperate bid to ensure his nani never forgets again, Zak enters her into the chess competition of a lifetime. But will Zak's nani remember long enough to play?