(NBC) The hit family drama "This Is Us" wraps up its first season tonight.

That has got some fans anticipating the episode with excitement, but also a small amount of dread for the revelations it may bring.

Last week's episode seemed to set the stage for details about something that happened in the past, the death of the Pearson family's patriarch, Jack.

"It's going to get stressful. I hope people are recovered from William's passing and are just bracing them for what's to come," says series star Milo Ventimiglia.

All that fans know about Jack's passing is that it's caused ongoing turmoil for daughter Kate.

"The actual moments in the show are going to impact people. They may be tough moments, but they're not without hope," Ventimiglia says.

That hopeful spirit, even in the midst of sadness, is part of the show's emotional roller coaster.

Photos | Beth on 'This Is Us' visits 11Alive