Five-0 is baffled when a highly skilled ring of thieves pulls off the heist of an armored car, killing two security guards but leaving the money behind. Their only lead in the case requires Danny to reluctantly ask his ex-wife for a favor.

It's Christmas in Hawaii, but instead of celebrating, Five-0 is negotiating a hostage situation when the man who killed McGarrett's father resurfaces. The murderer, Victor Hesse, threatens to detonate an explosive that he's strapped around Chin Ho's neck.