At a Mor Lam stage... The Samnieng Thong troupe is putting on a performance. "Saifah" (Tao Phusilp) is singing on stage and invites his younger sister "Fonthip" (Kharittha Sangsa-opas) to sing with him. However, an unexpected event occurs below the stage when a major mafia syndicate, the Red Dragon gang, clashes with a rival gang. A chaotic brawl ensues, and a stray bullet hits Saifah while he is singing, killing him instantly. Since then, Fonthip becomes absolutely terrified of singing.
Meanwhile, "Mawin Ayasit" (Prem-anan Sripanich) is in a knife fight with "Pongthep" (Phusana Buangam), a former best friend who had fought side-by-side with him for a long time. They have fallen out due to different ideologies. Mawin wants to lead the organization towards the light according to their grandfather's (Lao Gong) will, while Pongthep wants to expand their dark influence and run all kinds of illegal businesses to get rich, backed by "Songphon" (Wiphop Bangyikhan), a senior secretary pulling the strings behind the scenes. Pongthep intends to kill Mawin in this duel because Songphon knows Mawin will be an obstacle preventing them from rising to power. In the end, Pongthep is defeated, allowing Mawin to become the supreme leader of the organization according to the executive board's resolution.
Having lost his dark businesses due to Mawin's crackdown, Pongthep plots to lure Mawin into a death trap without letting "Darin" (Wanrada Phetchamnan)—Mawin's naive younger sister and Pongthep's lover—know about it. Pongthep fakes a situation where Mawin has a conflict with a rival gang, leading to a fierce battle. Barely surviving, Mawin flees for his life with "Chan" (Sukrit Songkaew), his close friend and trusted bodyguard. Pongthep disguises himself as an assassin to hunt Mawin down. Chan protects Mawin until he is shot and injured. Fleeing from Pongthep's pursuit, a battered Mawin unfortunately gets hit hard by a car, falls, hits his head on the ground, and falls unconscious.
Fonthip steps in to help and brings Mawin to the Mor Lam troupe for treatment. Mawin wakes up with amnesia; all his memories are gone, and he can't even remember his own name! His personality also changes. From a quiet, resolute, and ruthless man, he becomes a cheerful, smiley, sweet, gentle, and timid guy who avoids conflict. Fonthip finds Mawin's face very familiar and vaguely remembers seeing him on the day her brother was killed. She intends to interrogate him about who killed her brother once he recovers. She presses Mawin about whether he was involved in her brother's death, but is disappointed when Mawin cannot give her any answers. Pitying his helpless state, she begs "Kru Saengthong" (Yingyong Yodbuangam) to let Mawin work for the troupe. Kru Saengthong accepts him and names him "Nai Khaen" (Mr. Khaen).
Meanwhile, "Kongla" (Akkarawat Jumphonwiwat), the lead singer of the Saengthong troupe, is unhappy with Mawin's presence and tries to frame him to get him kicked out, but fails. Kongla is then bought out by "Sia Banjerd" (Thanapon Sammaprot) for a higher price than what Kru Saengthong pays, so he decides to leave and join Sia Banjerd. Kru Saengthong and the troupe members are devastated by Kongla's departure. Fonthip asks Kru Saengthong to mold Khaen into the new lead singer to replace Kongla, because she once accidentally heard Khaen sing beautifully. Fonthip believes Khaen is the one who can revive the Samnieng Thong troupe, though Khaen himself lacks confidence.
At the same time, Khaen discovers that Fonthip has a talent for singing and begs her to perform. However, Fonthip is traumatized by the memory of her brother getting killed the last time she sang with him, which has remained a deep-seated complex for her. Eventually, Khaen manages to help her overcome this trauma.
As for Chan, who has been searching for Mawin at the same time as Pongthep, he finds Mawin first and is shocked to discover that Mawin has become a Mor Lam singer. Chan disguises himself and joins the troupe to help Mawin. Chan asks Mawin to meet his sister, Darin, to help trigger his memories. On the way back to the troupe, an incident occurs: Chan encounters the rival gang, leading to a clash. Mawin's memories return. He is shocked to realize he is a mafia boss, and that the Red Dragon gang needs him to return and take over as the supreme leader from Pongthep and Songphon, who are currently controlling and ruining the organization. Meanwhile, Kru Saengthong's Mor Lam troupe also desperately needs "Mr. Khaen," the Mor Lam singer, to help save the band's situation.
