Set in 1999's rampant violence, the story follows the intense bond of friendship between girls during a scorching summer.

Jina is the top employee at a credit card company call center. She avoids building close relationships, choosing instead to live and work alone – until she is suddenly tasked with training a new recruit.

Honed from childhood into a merciless killing machine by a criminal organization, assassin Sook-hee is recruited with the promise of freedom after ten years of service. However, secrets from her past destroy everything she’s worked for and now she embarks on a roaring rampage of revenge.

A niece who lost her parents and grew up in the hands of an uncle who runs a shopping mall faces a new truth after her uncle's sudden death.