A year after the incident at Clamp Tower Billy and Kate are finally managing to settle down along with Gizmo. But, when water is accidentally dropped on the Mogawi and a new one is formed not all is what it seems. The new Mogawi may seem nice and take to Billy and Kate well, but Gizmo has his doubts.

He has everything planned. Everything, right down to getting shot. Or so he thought. When a moment in a case goes horribly wrong, how will Sherlock react when this time he must save his doctor's life. Post-His Last Vow with minor spoilers