Ali Ferguson has just moved into Lever Tower with his mum. It's not long before he meets Caitlin & the Alsatian dog she looks after, Falcon, who doesn't take too kindly to being walked on a lead. Caitlin introduces Ali to her best friend, Gez, & together the three set out to discover, firstly, why the foxes have disappeared from the area, secondly, why the owls have appeared &, thirdly, why Miss Osborne has, it seems, vanished... And how exactly her disappearance is related to the previous two. With the help of his friends &, significantly, Caitlin's dad, Ali & his mum begin to feel comfortable & happy in their new life without Ali's dad.