Ryan Alosio

While investigating the death of a bridesmaid at a wedding, Castle runs into an old flame (Alyssa Milano).

When the remains of a young documentary filmmaker are found in a ventilation shaft in an underground Washington, DC, tunnel, Brennan and Booth must venture into the maze of tunnels beneath the city and are surprised to discover a world of homeless shelters underground. Clues lead them to suspect that a man living underground was involved with the murder, but instead he gives them valuable information about the purpose of the victim's underground project.

With only five hours left, the clock races toward the climactic series finale as Jack stops at absolutely nothing to avenge the emotional setback of losing his beloved partner Renee Walker. Meanwhile, the administration attempts to keep the historic and pivotal peace agreement on track as undermining forces surface.