[s2e1] Deep In Death -

The team discovers the victim was an insurance agent who had been laid off for months. To cover his debts to a Russian poker ring, he had turned to smuggling cocaine inside his body as a drug mule. Castle’s Personal Stakes

The mystery begins with a startling discovery: a man found dead and tangled in the branches of a tree. The investigation takes a turn for the surreal when:

Beyond the case, Castle faces professional pressure. He is struggling to finish his latest novel, under a looming deadline while simultaneously trying to "build a door" through the wall Beckett has put up between them. "Castle" Deep in Death (TV Episode 2009) - IMDb

The episode finds the central duo "on the outs" after Castle crossed a major line: investigating the cold case of Beckett's mother’s murder without her permission. While Beckett is still "plenty peeved" and initially wants Castle gone, she is forced to work with him again when a bizarre new case lands on her desk. The Case of the Man in the Tree

Season 2 Premiere: " Deep in Death " – Tension High as Castle Returns

While being transported to the morgue, the coroner's van is intercepted at gunpoint and the victim's body is stolen.