H.I.V.E. 6: Zero Hour by Mark Walden

Overlord is reborn, and has developed the chilling ability to move from body to body, erasing the host's personality and ultimately killing them, forcing him to hop from victim to victim. He must find Otto, the only host designed to contain him, and for that he needs the location of H.I.V.E. He also plans to take control of a secret US Army facility that is home to the Autonomous Weapon Programme, a computer-controlled system uniquely vulnerable to his control.

Nero is forced to activate Zero Hour, a plan designed to deal with any member of G.L.O.V.E. on the brink of true global domination. Nero also knows that Otto must not be allowed to fall into Overlord's hands, and a desperate race across the globe begins. The stage is set for a final battle with Overlord. Little do they know that he has a final weapon in his arsenal, on a scale unlike anything they have ever seen before.