Hawaii Five-0's 150th episode is in the works.

The CBS series will hit a milestone in season 7, and writers have cooked up a special hour to celebrate. Titled "Ka makuahine a me ke keikikane" (which roughly translate to "Mother and Son"), episode 7 went in front of the cameras ahead of Labor Day weekend. As a few familiar faces hopped flights from the mainland, showrunner Peter Lenkov gave fans a sneak peek at last Friday's schedule.

 #h50 @hawaiifive0cbs 150th episode starts today!!

A photo posted by plenkov (@plenkov) on Sep 2, 2016 at 7:10am PDT

As you can see, Sara's future will still be up in the air. Chin was initially against taking in Gabriel's daughter, but season 7 sneak peeks show the uncle and niece growing ever closer. Viewers can certainly expect the case to tug on their heartstrings.

Got the feels watching DDK as Chin Ho in this very feelsy moment. #H50 A photo posted by Grace Su (@gracesu_) on Sep 3, 2016 at 12:49pm PDT

Meanwhile, the return of Doris McGarrett (Christine Lahti) and Wo Fat's father will give Steve McGarrett a chance to get the answers he's been looking for since season 1.

"It's really a mythology episode," showrunner Peter Lenkov told TV Line. "It will tie up some loose ends and spark a new storyline in the episode that follows."

In addition to Lahti, Michelle Borth (Catherine) and Sarah Carter (Lynn) will also return. The actresses arrived for filming over the weekend, and Lahti and Carter took to Twitter to tease their return.

Are you excited for the 150th celebration? Sound off in the comments below!

Hawaii Five-0 will return to CBS on Sept. 23 at 9 p.m. ET.

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Tags: Hawaii Five-O television CBS