John Warren, a musician with the Anchor Ensemble, the Navy's most elite band, jumps from their bus into traffic during an impromptu jam session. Senior Chief Musician Neil Marzad said Warren suffered from depression. Jimmy says it wasn't a suicide but that Warren was poisoned instead by one of his bandmates. Gibbs receives a text and puts McGee in charge for the next couple of days. Gibbs is going to help Fornell, whose daughter Emily is going into rehab. Jack's biological daughter Faith wants to get coffee with her. Kasie discovers that Warren's clarinet reed was poisoned. But Neil identified it was Hannah McClain's reed. She was the real target. Hannah said the band has a stalker they had dubbed "The Nugget Creeper." Jack chases off an old lady so she can have a table for her and Faith. McGee and Kasie finds Andrew Hoffer on surveillance. Gibbs left his cell phone, wallet, and badge. When arrested by Torres and Bishop, Hoffer says he was trying to protect Hannah. Hoffer has an alibi since he was working a double shift. He says there's a secret society within the band. Three former band members have recently disappeared and the conductor is missing. Faith asked Jack to fill out a medical-history form. Hannah said the conductor had called her last night to tell her he had something special planned for her. Kasie tracked his second cell phone. The band holds a special ceremony for members who have passed away annually. There was nothing suspicious about the three disappearances in the end. Kasie determines all the instrument cases were heavier than normal, as they were being used for smuggling heavy metals by the equipment manager. Everyone then attends the Anchor Ensemble concert, including Gibbs.