Hawaii Five-0 will jump back in time during "Ho'oilina (Legacy)," taking viewers back to when Steve McGarrett was just six years old.

Wo Fat Heavily Armed In New 'Hawaii Five-0' PHOTO, 100th Episode Wraps

The flashback will come as a fully-grown McGarrett (Alex O'Loughlin) takes on one of his father's old cases. After coming across Ellie Clayton (Mirrah Foulkes) at John McGarrett's grave, the Five-0 leader will decide to investigate her cold case using a lead his father uncovered just before his demise.

As he does so, the episode will bring in six-year-old McGarrett and a young Ellie, played by Nicolai Makana Perez and Chanel Marriott.

Danny Tells Family About Matt's Death On 'Hawaii Five-0', Will He Go Back To New Jersey?

In the present day, Steve and Ellie will have the chance to become friends, but probably no more than that.

"Everybody's selling it as a love interest, but really it's a friendship," said executive producer Peter Lenkov, according to TV Line. "McGarrett meets a woman on the anniversary of his father's death, and they share the common trauma of both losing a parent very early on. And that's going to play into an arc."

Find out more when Hawaii Five-0 airs Fridays at 9 p.m. ET on CBS. Click the video below to see a preview for the series next episode.