The unique title is taken from a French saying "entre chien et loup" and refers to the moments after sunset when the sky darkens and vision becomes unclear, making it difficult to distinguish between dogs and wolves, friends and foe.

One day, Soo-hyun leaves for an operation dealing with the Cheongbang, only to return in failure because of the resurfacing terrible childhood memories of when he was in Thailand.

Due to his thirst for personal revenge and ignoring orders, Soo-hyun was fired and stripped of his title as an NIS agent.

Through Chief Jung's proposition, Soo-hyun becomes an undercover NIS agent after staging his own death (car accident).

Meanwhile, Min-ki has fallen in love with Ji-woo and she begins to consider his proposal to officially court and forget Soo-hyun.

At the fighter's resting room, he overheard conversation between a Cheongbang's Mini Boss and his subordinate planning to kill Mao.

He hides her from the Spider gang by dropping her off behind the containers and backs right out of the dead end to engage in a dangerous car chase.

Soo-hyun gets shot in the head and loses control, his car then falls off the port wharf into the sea.

Over the span of the next episodes, Min-ki and an old ex-NIS agent and restaurant owner form an investigation team secretly with two other NIS employees.

Source: TNS Media Korea It aired in Japan on satellite channel WOWOW in February 2008.