Hye-young Jun Ji-hyun is an artist who earns a living by sketching portraits for 30 euros each, capturing the lines and stories of the people she encounters in the mountains. Park Yi [Jung Woo-sung] is a skilled, quiet professional hit man who, from a distance, sees her at her stand of paints and instantly falls for her. Their fateful encounter unfolds on a narrow channel where a log becomes a makeshift bridge, and a lost art bag becomes the seed of a fragile connection that will redefine both of their lives.
When Hye-young slips and loses her bag while crossing the water, Park Yi rushes to help, but finds her gone. He salvages the bag and replaces the log with a sturdy bridge, a gesture that transforms the moment into a small miracle. The next time she returns to paint, she discovers the bridge and the bag’s return stitched into a quiet, hopeful message. She completes her painting of the mountains and leaves it in place of the bag as a heartfelt thank-you to the anonymous builder.
From then on, a daily ritual begins: at 4:15 pm sharp, daisies arrive for Hye-young. She grows intrigued by the sender’s humor and warmth, and a soft affection sprouts. Park Yi, aware of the danger that shadows his line of work, keeps his distance, torn between his love and the need to protect her from the world he inhabits.
Jeong Woo [Lee Sung-jae] is an Interpol detective chasing a drug ring. While tracking the criminals, he crosses paths with Hye-young at her portrait stand, asking for a portrait as part of his investigation. This routine encounter becomes a recurring thread as he quietly observes the crowd and the activity around her. Soon, the drug dealers realize someone is watching their moves, and the danger grows closer to both of them.
Hye-young begins to believe that Jeong Woo is the flower sender, and she develops strong feelings for him, while Jeong Woo hides his own emotions to keep his investigation intact. Park Yi watches the duo closely, ready to intervene if the line between his world and theirs crosses too far.
The tension escalates when armed gangsters close in. Park Yi acts in a desperate bid to protect Jeong Woo, firing his sniper rifle to fend off the attackers. In the process, Hye-young is shot in the neck as she tries to shield Jeong Woo, and the injury leaves her mute. The guilt weighs heavily on Jeong Woo, who accepts responsibility for the cascade of violence that followed.
Jeong Woo is transferred back to Korea, leaving Hye-young to cope with the tragedy and Park Yi’s presence that haunts her days. Yet Park Yi cannot fully disengage and continues to watch over her, even as she remains torn between memory and longing for Jeong Woo.
A year passes, and Jeong Woo returns to the Netherlands to offer an apology. His boss pushes to unravel the truth behind the earlier events, and a sharper investigation reveals Park Yi’s real identity as a professional killer. A trap is laid to draw out the killer by targeting Jeong Woo.
Backroom politics come to the fore as Jeong Woo’s boss contracts Park Yi’s dealer to kill Jeong Woo, hoping to finish the matter once and for all. When Jeong Woo arrives with undercover protection, Park Yi confronts him in private, and Jeong Woo feints waiting for a moment. The plan spirals out of control as Jeong Woo, now surrounded by cops, is shot in the head by an assassin belonging to Park Yi’s organization—an act that forces Park Yi to reveal his true self and his refusal to kill Jeong Woo, even as the other killer’s bullet strikes.
The truth comes to light through hints from Jeong Woo’s boss, and Hye-young realizes that Park Yi was the source of the daisies. With this revelation, she confronts Park Yi and tries to stop him from killing his boss. The attempt ends badly when the assassin responsible for Jeong Woo’s death targets Park Yi, and Hye-young, in a last act of protection, interrupts the attack by catching a shot that would have claimed Park Yi’s life—dying in the process.
In the aftermath, Park Yi sinks into a rage and exacts revenge on his gang, confronting his boss, President Cho, in a tense Mexican standoff. They exchange gunfire, and Park Yi staggers away, wounded but alive in the street.
In the final scene, an epilogue paints a quiet moment: Park Yi, Jeong Woo, and Hye-young stand among a crowd waiting for the rain to stop, their eyes meeting and a shared, fragile smile passing between them amid the lingering storm clouds.
