Smallville Season 4 Plot Introduction: Chloe, who died in an explosion accident, left a tape for Clark, hoping that Clark would find her killer. After Chloe's cousin Lois watched the tape, she drove to Smallville to find Clark but got lost due to taking a wrong turn, and accidentally met Clark lying naked on the ground in the cornfield.
Clark had completely lost his memory, so Lois took him to the hospital. Martha, Clark's mother, was at the hospital all day taking care of Jonathan, her comatose husband. Martha recognized her son in the corridor and took him home. However, this Clark was actually Carrol, who didn't recognize his own family and flew away, leaving his mother behind. Bridgette Crosby came to the Kent house and found a heartbroken Martha, handing her a Kryptonite stone. The brave Martha took the stone and found Carrol, pointing the stone at his chest, and successfully brought her son Clark back. When Clark returned, his father also recovered from brain death and returned to normal.
Lois went to her cousin's grave to lay flowers, and Clark invited her to stay at his home, hoping they could work together to find out who killed Chloe. As Clark was looking at Chloe's grave, he told Lois that Chloe was still alive.