Hawaii Five-0's Catherine Rollins disappeared with a major secret. Now, half a season later, McGarrett will finally find out the truth.

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The McRollins ship came to a thunderous halt just as Steve (Alex O'Loughlin) was about to propose, and while Cath (Michelle Borth) told her former beau that she was leaving him to help earthquake victims in Nepal, she was really embarking on some clandestine government mission. When episode 18 rolls around, viewers will join McGarrett as an NSA case blows he doors off Cath's lie.

"McGarrett and Five-0 must track down a Russian spy who has stolen a flash drive containing classified NSA information that puts the life of a member of their Ohana at risk," CBS said of "Waiwai (Assets)." "Also, McGarrett finally learns why Catherine left him, and Abby continues to conceal her actual mission from Chin and Five-0."

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According to the announcement, Borth will not feature in the episode. It remains unclear whether or not she has another appearance lined up for season 6.

Showrunner Peter Lenkov previously teased the March 11 episode with a brief clip. Watch as an apparent NSA agent name-drops Cath in a conversation with McGarrett.

 Hmmmmmmmm.... #H50 editing

A video posted by plenkov (@plenkov) on Jan 26, 2016 at 5:18pm PST

Hawaii Five-0 airs Fridays at 9 p.m. ET on CBS.

Tags
Hawaii Five-O, Television, CBS