Brian Gross

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.

When Caroline's effort to sell cupcakes to a trendy new coffee shop in the neighborhood fails after the owner says they aren't pretty enough, she persuades Max to take a cupcake-decorating class.

Caroline and Max spend their spring break dog-sitting at a couple's lavish apartment.

Xander and a group of obnoxious students start acting strangely after entering a quarantined hyena exhibit at the zoo.

Abby risks her career in defense of a dog that authorities believe is behind a fatal mauling; Gibbs tries to ferret out the secret Jenny is keeping.