"The Hunt For Xavier" is an X-Men storyline that ran in the fall of 1998.
According to script writer Joe Kelly, "The Hunt for Xavier" was the "last straw" that led to his and Steven Seagle deciding to leave Marvel Comics.[1] The writers were frustrated with their loss of freedom in developing the story arcs.[1]
Plot
The X-Men attempt to find the location of Professor Xavier, who has been missing ever since the authorities arrested him in the wake of the Onslaught disaster. Their quest for him leads them once again into the path of Cerebro, the mutant detecting device used by the X-Men which has now gained sentient life. This time, it has gained a new form, as opposed to mimicking Charles Xavier and creating a team of fake X-Men. Cerebro has begun kidnapping mutants left and right to "catalogue" them and has begun targeting members of the newly reformed Brotherhood of Evil Mutants