Michonne is a quiet but fierce warrior who saves Andrea from walkers with her katana blade after the battle at Hershel's farm. She and Andrea spend the winter together, fending for themselves as a close-knit team.
When Andrea falls sick, Michonne cares for her and scavenges medicine in a walker-infested pharmacy. Andrea is on the verge of death, however, when Merle discovers them near a helicopter crash site. He brings them to an idyllic town, Woodbury, where they meet the Governor.
Though Andrea is immediately taken with Woodbury, Michonne harbors a deep mistrust of the Governor, who refuses to hand over her confiscated katana despite her repeated requests. She breaks into his apartment to retrieve the sword and later discovers that he keeps cages filled with walkers. Afterwards, she packs her bags and implores Andrea to leave with her, but Andrea refuses and the two part ways.
After Michonne leaves Woodbury, the Governor sends Merle to kill her. She kills two of Merle's men and escapes, and then witnesses Merle kidnap Glenn and Maggie.
Michonne finds the prison and reports to Rick about the abduction. She offers to show the group how to gain entry into Woodbury to rescue Glenn and Maggie. During the rescue, she sneaks into the Governor's apartment and discovers Penny, his undead daughter. She kills Penny and stabs the Governor through the eye when he finds her.
Although her secretive nature initially has Rick on his guard — he briefly considers a request to hand her over to the Governor in exchange for a cessation of hostilities — she eventually gains the group’s trust and proves to be a valuable asset in defending the prison against Woodbury.
After successfully staving off the Governor's forces, Michonne is part of the team that goes back to Woodbury and discovers Andrea dying of a walker bite in the Governor's torture chamber. Ever the devoted friend, she stays by Andrea's side while Andrea shoots herself.