Christine Lahti Returns as McGarrett's Mother on 'Hawaii Five-0' (PHOTOS)

Meredith Jacobs

McGarrett (Alex O'Loughlin) is heading to Mexico in Friday's episode of Hawaii Five-0.

Christine Lahti returns as Steve's mother, Doris, when the CIA informs her son that she's gone rogue on her undercover mission and may have killed her partner. Can he bring her home and prove she's innocent? O'Loughlin wrote and directed the episode.

'Hawaii Five-0' Star Confirms Season 10 Exit — Will He Be Back?

'Hawaii Five-0' Star Confirms Season 10 Exit — Will He Be Back?

The CBS series toasted to its 10th season while also bidding farewell to a longtime member of the team.

Click through the gallery above for a look at McGarrett in Mexico, reuniting with his mother, and more.

Hawaii Five-0, Fridays, 8/7c, CBS