sentences:  Sylvan accidentally activates the TARDIS, sending him, the Doctor and Felicity fifty years into the future.There, Sylvan's brother, Dega, is now king and has used the Doctor's device to begin turning his people into Cybermen.He has constructed a space fleet with which he intends to invade the mineral-rich Earth, and plans to kill any unconverted Mondasians with cyanide gas.