'This is Us' season 1 episode 18 spoilers: Milo Ventimiglia teases 'stressful and a little sad' finale; when will Jack's death be explored?

The big three must make major decisions for their future on the upcoming finale of NBC's hit drama "This is Us" season 1.

Titled "Moonshadow," the show's 18th episode will see another emotional scene featuring Jack (Milo Ventimiglia) and Rebecca (Mandy Moore). According to the official synopsis, Jack is determined to make things right with his wife. He heads to Cleveland to meet Rebecca during the night of her first major gig with her band. Meanwhile, the Pearson siblings must also deal with issues of their own. Randall (Sterling K. Brown), Kate (Chrissy Metz), and Kevin (Justin Hartley) make big decisions that will have a huge impact on their futures.

One of the greatest mysteries of the show is Jack's death, and fans have been wondering when that storyline will be explored. It was revealed earlier in the season that Jack is already dead in the present timeline, and his ashes are in Kate's home. However, the series has yet to show when and how he died.

Metz, who plays one of Jack's kids, recently caught up with Glamour Magazine (via Buddy TV), and she talked about what's next for the NBC drama. When asked if season 1 will address Jack's death, the actress had this to say: "Not specifically. I think they're going to string that out as much as they can. [Laughs]"

On Wednesday morning, Ventimiglia also shared details about the last two episodes during an interview on The Today Show. He assured fans that Jack will still be around when the program finally addresses his passing. "I do know, how, when, and why. I know everything," he said. "Jack will always be around. Even now – we know in the present day his character is no more – but he will be around when we reveal his death...The last two episodes I already watched and they are a pretty stressful and a little sad. They are also funny," he added.

The final episode of "This is Us" season 1 airs on Tuesday, March 14, at 9 p.m. ET on NBC.