James Swan went to a bank and an abandoned building before he was killed. Lanie learns that the victim never had any of the standard immunizations everyone gets as kids. A stop to see a suspect who was suing the guitarist over a song doesn’t pan out, but it leads Castle to believe Swan was planning to go solo. This would likely tick off the other band members like Keith, whose boots make sounds like horse hooves walking in the snow. Keith denies killing James, but says his band buddy hasn’t been the same since a gig they did in Ithaca. A video showing Keith having sex with a groupie gives him a really raunchy alibi.

Ryan learns that James was raised in a cult located in Ithaca. That explains the lack of vaccinations. It also sheds light on the “observe” tattoo on the victim’s arm. It originally read “serve.” James added the extra letters after he escaped. He was likely worried someone recognized him when the band played in Ithaca. The cult’s violent leader, John Campbell, did 10 years for murder before starting a church that doubles as a marijuana farm. He was also in town the day James Swan was killed.

Castle and Beckett are caught on camera in a very lovey-dovey way. Not good. They’ll have to worry about that after they interview another cult victim. She heard Campbell swear he’d get revenge on Swan, who may have been trying to buy his freedom for $25,000. Beckett goes at the cult leader hard, but she has no evidence to arrest him. The bad news continues when she learns that Captain Gates will be going through all the precinct footage shot by the documentary film crew. Gulp.