In the pilot episode of "Butterfly," David Jung, a Korean-American man who faked his death nine years ago, confronts his past when his daughter Rebecca, now working as an assassin for the private intelligence agency Caddis, is sent to kill him.

David and Rebecca find themselves on the run from Caddis after a tense encounter at a police checkpoint. But their unexpected reunion is complicated by Rebecca’s resentment over her father's abandonment.

Rebecca, David and his family escape to a safe house in the coastal city of Busan. Family tensions mount as Rebecca struggles with her father's new family. And a shocking revelation about David’s past with Juno is revealed during a violent confrontation at a marina.

After abducting Oliver, David and Rebecca use the information they gather from him to devise a plan to go after Juno, taking them back to Seoul, where Gun and Caddis are waiting.

Juno interrogates Oliver and discovers he betrayed her while being held captive by David. Meanwhile, David and Rebecca carry out a PSYOP campaign against Juno, aimed at dividing her and Oliver and bringing down Caddis once and for all.

David pursues Rebecca after she's captured by Juno and Caddis operatives, leading to a high-speed chase and brutal ambush at an abandoned factory site.