When mortals try to kill Amanda in her sleep, she goes to MacLeod for help. He thinks it could be some renegade Watchers. Amanda and Mac figure out that they are after her crystal, a piece of the legendary Methuselah's Stone. When she tries to steal back the rest of it, she finds Methos there, stone in hand. Is the 5000 year old man trying to become invincible? Or is there another reason he's after it?