Lois' undercover assignment reveals a deadly foe that promises to change the Kent family forever. Meanwhile, the Kent boys find themselves being pulled in opposite directions.

Lois and Chrissy pursue a new lead in the Mannheim investigation against Clark's wishes. Meanwhile, Jonathan, Jordan, and Nat face an unexpected obstacle.

Clark and General Lane are both having a hard time giving Lois room to make her own decisions. Meanwhile, Lana and Sarah have a run-in with an old friend at the diner.

Lois and Clark dig deeper on Bruno Mannheim, starting with his connections to Hob's Bay Medical Center, while Jonathan and Jordan panic at home over Lois' dire diagnosis.

Superman and John Henry clash over how to handle Bruno Mannheim, while Lois worries over upcoming treatments and confides in Lana about her early courtship with Clark.

Clark helps Lois prepare for a procedure but must leave the boys with her to help John Henry and General Lane track down the Mannheims.

All of Smallville comes together to view a meteor shower, and Lex Luthor makes his move to take down Superman and Lois.