Mick and his friends fought off the threats to London's time travel alleys, but they suspect those efforts were only the beginning. So when people start getting attacked in the real world, and the time alleys start flickering with unexplained lightning, they're pretty sure that danger is soon to follow. As the threat materializes, the Forsyth Institute once again presses Mick and his uncanny alley sight into service to protect the alleys and the kids inside them.

But this time, the threat is greater than Mick expected, and its source is more shadowy and powerful than anyone imagines. Despite all their efforts on London's streets and waterways, Mick and his friends may not be able to stop it. And even if they can, they may not be able to bear the price to be paid.