'This Is Us' Preview Says 'Hidden Truths' Will Be Revealed in Season 3, Episode 6

This Is Us promises answers to "Jack Pearson's biggest mystery yet" on the next episode of the NBC drama.

In the promo for the series' next episode, titled "Kamsahamnida," the family is left to deal with certain secrets and hints that came to light in the previous installment.

"Dad gave me her necklace. That meas something," Kevin (Justin Hartley) says, recalling the photo of his father and a woman he received in the previous episode.

"Vietnam, that was a chapter in his life he didn't want us to know about," Randall (Sterling K. Brown) tells his brother.

As for Kate (Chrissy Metz), she handles with finding out about her husband's battle with depression and unsure about what to do next.

"I don't know if I should be pushing him or let him take his time," she says, as Beth (Susan Kelechi Watson) admits to her husband that she has been struggling since getting laid off from her job.

"I'm not fine," she says after a clip of her telling her kids to shut up plays quickly.

The latest episode left Kevin getting a big clue as to Jack Pearson's (Milo Ventimiglia) time in Vietnam, when Robinson gave him an old photo of his father in Vietnam standing beside a woman who was wearing the necklace his father later gave him.

Kevin has become interested in Jack's time in Vietnam since receiving rave reviews for his performance in the movie he filmed during season 2. Due to flash forwards shown during the season two finale, viewers know that Kevin's curiosity will eventually take him and is girlfriend Zoe (Melanie Liburd) to Vietnam; with some fans speculating Jack may have had another child during the war.

Kate received good and bad news during the the latest episode, as she and Toby were finally able to get pregnant. However, the stress of the endeavor, plus stopping his anti-depressants altogether, led to Toby (Chris Sullivan) having a meltdown.

Randall had some trouble getting his political campaign for city council in trouble, as Beth found out she had been affected by being laid off much more than she first believed.

In the past, viewers got an inkling of Jack's time in the war in a previous episode, exploring his relationship with his brother Nicky, however the episode left the door open for more story given that we only saw when Jack found his brother in Vietnam.

This Is Us airs Tuesdays at 9 p.m. ET on NBC.