Hawaii Five-0
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Season 6 Episode 17 of "Hawaii Fivr-0" is titled "Waiwai," which translates to "Assets," and it will see McGarrett, the character essayed by Alex O'Loughlin, finally learning why Catherine left.

Catherine last made her appearance in Season 6 Episode 3 where McGarrett was told she was leaving to help in the aftermath of the Nepal earthquake. However, it was a lie and McGarrett will come to know the truth about Catherine's true mission in this Friday's episode.

Will this affect McGarrett's relationship with Lynn? McGarrett seems to be over his old love, as the Valentine's Day special saw the Navy Seal deleting Catherine's number from his phone. However, it is too soon to say if Catherine is really gone from his life. There is no official word on whether Michelle Borth, who plays Catherine, will return to the show, but the possibility cannot be ruled out as the series has thrown a number of surprises in the past.

Although the promo for the episode shows Catherine in trouble, the scenes featuring her are supposedly flashbacks. 

Another relationship that will be explored is that of Abby and Chin. Abby, who has been planted as a mole to keep tabs on McGarrett's team, is still harbouring secrets from Chin and it won't be long before the truth emerges. Will Chin forgive Abby for lying to him?

"I think the odds are fairly good. I hope. I think that, ultimately, Abby is trying to do the job that she was hired to do. They will have to work through a lot, obviously, to get to the other side, but I do hope that there's a happy ending for the two of them. Chin really needs a happy ending!" actress Julie Benz told TVLine.

"Hawaii Five-0" Season 6 Episode 17 will be aired Friday on CBS. Click here to watch the episode.

The official synopsis reads:

A Russian spy steals a flash drive containing classified information that puts a Five-0 member at risk; McGarrett learns why Catherine left; Abby keeps her mission a secret.