This episode of NCIS: Los Angeles opens with a man having fun at the beach while riding a jet ski. Unexpectedly, he slumps over the handlebars while his jet ski goes full speed at a group of people standing on shore, where he crashes against a chain link fence. As some of the onlookers rush over to help, they open his flotation vest and discover he has been shot.

It turns out that the young man is believed to be a scientist that defected from North Korea.  He was working on a highly classified military project that he was getting ready to sell to the US government before he was killed by the sniper.

The man had a partner in the business, but when Sam and Callen go to visit her they find she has been bludgeoned to death with a lamp.

NCIS Director Leon Vance arrives unannounced and informs the team that the sniper is a highly skilled assassin named Lee Wuan Kai. It turns out that early in his carrier Vance crossed paths with the killer and was lucky to escape with his life. From that point forward he has been obsessed with bringing her in, dead or alive.

As the NCIS: Los Angeles team continues to investigate, they discover the murdered man has a twin brother who was actually the brains behind the secret military project and his brother was simply taking credit for his work.

As they are closing in on the assassin in her hotel room, Vance gets a surprise call from her. She goes on to inform him that she did not kill the woman that was murdered with the lamp. Later, the brother’s wife admits she killed her because the woman threatened to have her husband deported and sent back to North Korea.

The episode ends in a pulse-pounding scene that has Sam and Callen shooting it out with Kai as she tries to escape from her hotel down through the parking garage. Her car slams into an on coming car as it hits the exit ramp, but on opening the door they find blood splatter but no Kai,who has apparently escaped them again.

This was a particularly well written episode of NCIS: Los Angeles that maintained a very high level of intrigue throughout the show.