From the moment they arrive there's something amiss - the weird hotel manager, the zombie-like guests and the insects everywhere - not what they expected from a sun holiday! And when the boys discover the Blobster - a monster made of slime and sludge that oozes from the pool to devour guests, things really start to get creepy...

Will Sophie believe them or will she think it's just another scary story? Can they defeat the Blobster before its horrible power spreads further and further afield?

It's a dangerous mission, but someone's got to do it!