The prequel follows Gibbs' early days at NIS.

Series stars LL COOL J and Scott Caan.

Plus, does Gary still have a future at NIS after being stabbed on the job?

Showrunners Gina Lucita Monreal and David J. North also break down key moments from the young Pride episode.

Guests will include Sean Murray, Wilmer Valderrama, Mariel Molino, Daniela Ruah, and more.

The long-running series is about to reach its 500th episode.

'We can't make it easy,' says Stowell.