In the wake of Cole's murder, Hetty is determined to find the killers. And the book.
Surveillance video from Cole's nursing home was disabled by the killers but a resident's nanny-cam helps the team get a grainy image of two men who Callen determines to be speaking Russian.
Mattias contacts Hetty to inform her that the CIA secured his release in exchange for the black book.
Hetty knows with Mattias and the Russians now looking for the book the team must work quickly to find it before it gets into the wrong hands.
Eric and Nell discover Renner placed encrypted binary code messages as to the whereabouts of the book.
He placed the code in pictures he posted online several months prior to his death. They find the code leads them to a safe deposit box at a local bank.
Callen, posing as Renner's attorney, goes to the bank to retrieve the book until the team realizes they are not alone and have the CIA and Russians watching them.
They try and execute a clever bait and switch but it doesn't go to plan and Kensi is taken hostage.
Mattias pressures Hetty for the book and the Russians set a time for exchange the book from Kensi.
Hetty has Nell create a fake black book in order to save Kensi from her Russian captors.
The plan works and Deeks helps to rescue Kensi. Callen and Sam find out that Mattias is actually helping the Russians and Hetty decides to meet with Mattias to put an end to the search for the black book, once and for all.