Just after his tenth birthday, the last thing Zak expects is to hear 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, 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 ot outwit and outdo him - and his friends - at every turn.