Suparburoot Saleum Saleu

Sing (Pasut Banyam), an Interpol agent from the FIA unit, is assigned a mission to take down "The Moon" syndicate. The group consists of wealthy individuals who bid on priceless artifacts from around the world, completely disregarding how the items were obtained or how many lives were lost in the process. Sing takes on the mission with his partner, Franco (Vinny Vincent Kinney). To go undercover, Sing stays with Nai Aum (Arun Pawilai), a street peddler, and his daughter, Waanta (Lalin Thanaphum). Sing becomes suspicious of Jet (Patcharin Judkrabuanpol), a beautiful woman who has two subordinates named Tom (DJ Poom) and Jerry (DJ Petjah).
Meanwhile, the Thai police force, led by Inspector Kongkiat (Kosin Ratchakrom) and Sergeant Juean (Prakasit Bowsuwan), is tracking the illegal smuggling and drug activities of Sia Chuck (Dilok Thongwattana) and his right-hand man, Thanong (Khosawis Piyasakulkaew). Even when the police confiscate illegal goods, the mastermind always escapes because Superintendent Narong (Nuekkid Boonthong) acts as their corrupt protector. Inspector Kongkiat tries to investigate Sia Chuck by getting close to Suphannika (Amrapass Jullakasian), assuming she is Chuck’s mistress. In reality, she is Sia Chuck’s highly overprotective and beloved daughter.
Sing's presence in Nai Aum’s house causes Waanta to fall in love with him, though Franco is secretly in love with Waanta. Through their investigation into a meeting between The Moon's men and Non (Ruengrit Wisamon), a drilling engineer, they discover that The Moon is actually after Japanese gold hidden inside a mountain and the legendary gun of General Roger. Jet and Sia Chuck are working together on this. However, seeing that Jet's progress is too slow, James (Peter Louis Maiocchi) travels from America to take charge himself.
Sing has to disguise himself as various people to gather intelligence. Being a brilliant inventor, he creates bizarre gadgets for self-defense. When taking down criminals, he often uses a signature finishing move, earning him the nickname "The Sleepy Gentleman." Inspector Kongkiat suspects that Sing is no ordinary man and might be a transnational criminal or one of Sia Chuck’s men. However, Kongkiat himself is framed as a drug dealer by Superintendent Narong—who is secretly Sia Chuck's mole—in an attempt to get him fired. Fortunately, Police Major Senee (Athiwat Sanitwong Na Ayutthaya), an honest officer, steps in to help.
Sing's mission becomes increasingly difficult. He must investigate Jet, who works for The Moon, navigate Sia Chuck's alliance with the syndicate, and evade police pursuit. James becomes furious when he finds out Sia Chuck is planning to double-cross Jet, so he orders Adams (Thawatchai Penpakdee), a highly lethal hitman, to launch an attack. This forces Sia Chuck to flee with his daughter for safety. Inspector Kongkiat relentlessly pursues Chuck's case until he realizes Suphannika is actually Chuck's daughter.
After falling out with Sia Chuck, James tries to drill into the cave himself. Sing secretly applies as a tunnel digger and discovers exactly what The Moon is after. Due to their close proximity, Sing and Jet unknowingly begin to develop feelings for each other. James is enraged when he discovers the excavated gold is fake and the target gun is nowhere to be found. Losing trust in Jet, James locks her up and orders his men to hunt down Sing, leading to a shootout at Nai Aum’s house. Nai Aum is injured, but Waanta is just relieved her father survives. During the chaos, Adams steals an invisibility cloak invented by Sing.
Amidst the investigation, Nai Aum runs into his old rival, Sergeant Juean, bringing up their past over Waanta's mother—who was once Juean's wife before leaving him for Aum. This sparks a feud over who Waanta's biological father really is. Franco is kidnapped and forced to build a radar to locate the antique gun, but they only find an old gun of the same model, not General Roger's actual weapon. James modifies the gun and puts it up for auction. MP Promphan (Chai Khunsriraksa), one of The Moon's members, wins the bid. When it is soon exposed as a fake, the members vote to strip James of his leadership position.
Jet regains James's trust by shooting Sing, but it is actually a setup to save his life. Sing is deeply moved that Jet risked her life for him. Franco warns Sing, fearing his friend will be heartbroken for falling in love with a criminal. Inspector Kongkiat faces a similar dilemma, struggling with his love for a mob boss’s daughter. Meanwhile, Franco tries to win Waanta’s heart. Waanta investigates her own lineage and discovers her grandfather was a Japanese spy who stole the gun. Even Nai Aum has no idea where his father hid it.
Sing disguises himself as "Nakara," a handsome and wealthy young man, to get close to Sia Chuck. Chuck likes Nakara for his wealth and wants Suphannika to choose him as a partner. Unaware of the truth, Inspector Kongkiat becomes intensely jealous of Nakara, leading to a fistfight. Suphannika takes Nakara's side, breaking Kongkiat's heart. Eventually, Kongkiat follows Nakara's advice: he reconciles with Suphannika, and they finally confess their true feelings to each other.
James takes Jet to Switzerland to retrieve member data, hoping to reclaim his position as leader. A mysterious figure tries to steal the data but fails. Jet returns to Thailand with James, and they set their sights on Nai Aum, the heir of the Japanese spy. Knowing Aum's true background, Sing and Franco deduce that the gun must be buried with Aum's father's corpse.
Facing obstacles in their romance, Suphannika and Kongkiat share a tearful farewell hug, but local gossip blows the incident out of proportion. This prompts Kongkiat to step up and ask Suphannika to marry him. Out of pity for his daughter, Sia Chuck agrees. At their wedding, James spots Nakara and, intrigued by his wealth, invites him to join The Moon. Sia Chuck is furious that Pol. Maj. Senee sends men to search his house during his daughter’s wedding. After the wedding, Chuck has a change of heart. He withdraws from The Moon and prepares to hide out in a forest cabin. Thanong refuses to abandon him and goes with him.
The FIA teams up with the Thai police to arrest James, knowing he is the leader of The Moon, but Jet helps him escape. Franco is angry at Sing for going soft and letting James get away. Realizing Jet saved his life, James trusts her completely and entrusts her with a cross necklace. Seeking revenge on the police for raiding his hideout, James attacks Nai Aum’s house, leaving Aum critically injured. On his deathbed, Aum entrusts Waanta to Sing, and Sing promises to marry her.
During the wedding procession, James orders Adams to ambush them. Adams fails to kill Sing because Jet secretly provides cover fire. Jet is then forced to kidnap Waanta herself, demanding Nai Aum trade General Roger's gun for his daughter. Franco successfully rescues Waanta and Nai Aum with the help of Sing and the police. After this incident, everyone realizes Waanta and Franco are truly in love. Adams tells James that Jet is a mole, but James refuses to believe him. Furious, Adams quits The Moon to pursue his own revenge.
Inspector Kongkiat finally recognizes Sing as his childhood best friend. Sing reveals his true identity as an FIA agent. Meanwhile, Sia Chuck sends evidence of Superintendent Narong’s corruption to the police before disappearing into the forest with Thanong. Refusing to go down alone, Narong implicates MP Promphan, and both are arrested.
James holds another auction for the retrieved gun, and Nakara is invited. The police successfully raid the event and dismantle The Moon, but James, Jet, Tom, and Jerry manage to escape. Suphannika goes into the forest to find her father but runs into James and Jet. James takes Suphannika hostage to force Sia Chuck to help him cross the border. Chuck signals Thanong to rescue his daughter, but the plan fails. James shoots at Suphannika, but Sia Chuck takes the bullet for her and dies from his wounds.
Sing, Kongkiat, Franco, and the police arrive to make the arrest. James fights Sing and falls off a cliff to his death. Adams arrives to take revenge on Jet, but Sing shields her and takes the bullet. Kongkiat arrives just in time and shoots Adams dead. Jet willingly surrenders to Sing.
After Sia Chuck's funeral, Suphannika decides to stay at her father's house rather than live with Kongkiat, but eventually gives in to her heart's true desires. Franco resigns from the FIA to open a detective agency in Thailand because Waanta and Nai Aum refuse to move to America.
Finally, Sing discovers the truth: Jet is actually an Interpol agent. The target she had been seeking all along was the list of The Moon's members, which was hidden inside the cross necklace James gave her. Jet takes on a new assignment with Tom and Jerry as her team, and she must coordinate with an FIA agent—who turns out to be none other than Sing. Jet and Sing team up once again to take down the bad guys.
(Follow the fun of this action-comedy drama, "Suparburoot Saleum Saleu" / The Sleepy Gentleman.)