The Uncanny X-Men, Vol. 1

Dr. Boliver Trask has announced to the world that mutants are an incredibly dangerous threat. The Professor challenges him to a public debate to sway his opinion, but Trask has come equipped with Sentinel robots that soon go out of control, attacking the Professor and others. The X-Men rally together, following the rebel Sentinel robots back to their base, following their only clue: the phrase "Master Mold."