Choi Soobin – a notorious mafia in the underworld, the leader of cold-blooded deals that no one dares to touch – was forced by his own family to marry someone he absolutely disliked. That was Choi Yeonjun, the same age as him, but like two opposite worlds.

Yeonjun was a fool and always stuck to Soobin like a shadow. From childhood to adulthood, Yeonjun always ran after him, grabbed his hand when he left, clung to him as if letting go would cause the world to collapse. Wherever Soobin went, Yeonjun followed. Whatever he did, Yeonjun wanted to know. Even though he was ignored and chased away, Yeonjun still smiled and said: “I’m fine, as long as I can be by your side.”

But Soobin didn’t find that pleasant. He was a quiet, taciturn person, always hiding behind cruel plans and bloody deals. He feared that the dark world he lived in would taint Yeonjun – that pure and foolish person.

Now, when marriage was arranged like a transaction, Soobin had to face a choice: push Yeonjun away like he always did, or learn to hold on to someone who always stayed for him – even if it was only in silence and lurking danger.