'Hawaii Five-0' season 7 episode 10 spoilers: Cold case reopened after witness undergoes hypnosis; Danny reconnects with sister

"Hawaii Five-0" returns on Friday, Dec. 9, with the episode titled "Ka Luhi (The Burden)" after a three-week hiatus. The 10th episode of the series' seventh season will feature a murder that happened several years ago as well as a family reunion for one of the members of the team.

According to the synopsis for the upcoming episode, the Five-0 will investigate a 10-year-old cold case involving the disappearance of a teen after new information is uncovered. The case will once again be investigated after a boy suffering from Posttraumatic Stress Disorder undergoes hypnosis and realizes that he may have been a witness to the murder.

In the trailer, the boy is seen in therapy and is put in a hypnotic trance. It appears that as a young boy, he saw someone burying a body in the woods. However, instead of finding the culprit, the team encounters a major roadblock.

"We have one major problem. The kid confessed," Danny (Scott Caan) tells the team.

Aside from the case, Danny will also have to deal with his sister, Bridget (Missy Peregrym), as she arrives in Oahu for a business conference.

"She is on a work trip, she's struggling back at home, and there's a very brother-sister, fight-y dynamic because he calls me out on some stuff," Peregrym told Entertainment Tonight Canada.

According to the "Rookie Blue" alum, her guest stint on "Hawaii Five-0" was short but in the span of five scenes, they were able to feature a lot of interesting events and details. Viewers will get to see Danny turn into an overly protective big brother as he becomes convinced that his sister may be getting too close with her co-worker.

"It annoys me, and we get into a huge fight over it," Peregrym added.

Season 7 of "Hawaii Five-0" airs every Friday at 9 p.m. EST on CBS.