Wendy is waking up at 5:30 in the afternoon, having slept all day after a late mission. She's off for another mission, but Lacey is curious why her boots that Wendy borrowed is covered in green insect goo. Wendy runs off when Lacey tries to get answers about where she works.
Wendy arrives at Middleman HQ and The Middleman has her clean out Carpassian Hog-Roach goo from the back of the Middlemobile. The Middleman is off to see the cowboy western Ride Lonesome, a cinematic treatise on rugged individualism starring Randolph Scott. En route to the theater, The Middleman realizes he's being followed and confronts his pursuer: Lacey. She explains she's visiting the theater for an art project on rugged male heroism. They go into the otherwise deserted theater together and as the movie starts, Lacey asks what he does for a living. He says that he and Wendy are international consultants who solve exotic problems. They're interrupted when the Middlewatch beeps and Wendy calls to inform him that a man drowned in his bed. The Middleman and Lacey share a brief moment before he meets Wendy at the Peckinpah Hotel. CSI investigator Cecil Rogers is already on the scene and has determined that the victim, Artie Atkins, drowned with water from the North Atlantic. There's no indication that the water was forced into the man. Rogers departs and a CSI team arrives. They say they've never heard of a Cecil Rogers.
Back at HQ, The Middleman and Ida try to track down Cecil and Wendy provide a sketch. Ida determines that Artie Atkins was a fence specializing in antiquities and collectables that had to be sold secret. She's matched him by phone calls to Johnny John. The duo goes to Johnny's apartment and find him in bed with a woman. He begs for five minutes and they reluctantly grant him the opportunity. They wait outside and strange noises come out of the apartment. They barge in to find that Johnny John's date is a succubus. They pull the two apart and Johnny says that he and Artie pulled a job and now someone's coming after them. Johnny admits that they stole a tuba from a bank vault.
The duo goes to see Roxy and The Middleman slugs her, saying their deal prevents her from stealing magical artifacts. The other succubi close in but The Middleman refuses to back down and threatens to blow everyone up with a bomb. Roxy explains that the tuba is cursed and the only musical instrument to survive the sinking of the Titanic. Anyone who hears it play drowns in the icy waters of the North Atlantic. Roxy heard about the theft and sent her people to try and recover it. red a crew to steal the tuba and then sent her minions to find it. The Middleman gives in and Roxy proposes a truce: if he fails to find and neutralize the tuba, she'll have her ladies terrorize every criminal in the city until it's destroyed or locked up. The Middleman agrees and she slugs him to seal the deal and get some payback.
At Middleman HQ, Ida starts scanning the world surveillance network and looking for mentions of the word "tuba." It takes a while. A long while. Wendy takes a break and goes back to the sublet. After chatting with Noser, Wendy suggests to Lacey that they go get some supper but Lacey has a date and slips heads out. She goes to the theater and meets The Middleman for another showing of Ride Lonesome. The Middlewatch goes off again and he explains that he's never seen the end of the movie. Lacey promises to stay to the end and let him know how it ends.
At Middleman HQ, Ida finds a web posting from a boy saying he's found a tuba. The boy, Arturo Arroyo, is the son of Gabriel Arroyo, the owner of the Peckinpah Hotel. Arturo is going to school that night to find a mouthpiece. The duo goes to the school and find Arturo… just as Cecil runs in and takes the tuba. They follow him out to the street where Johnny John shoots Cecil and escapes with the tuba. Cecil says being shot in the heart really hurts… and heals the damage.
They take Cecil to HQ and interrogate him, and Ida determines that he's had a number of high-risk careers over the years, but no birth certificate or social security number. The trail leads back to a birth certificate for Cecil Calloway Rogers, a tuba player on the Titanic. Cecil takes the photo and then says that he was on the Titanic when it sank, and wrapped his tuba in a blanket and got into a lifeboat claiming it was a baby. Because of his cowardice Cecil is cursed to live for all eternity as long as the tuba is unharmed, forced to ponder the lives he took. However, he's actually pretty happy with his life as an immortal. He put the tuba in a bank vault but it was stolen, and he wants to get it back to insure his immortality. Arthur Mendelson, a philanthropist, stole the tuba and is a Titanic memorabilia collector. Mendelson plans to throw a party on his own ocean liner and have the string quartet from the Titanic play. Cecil refuses to get on a boat, since he doesn't want to risk drowning over and over again.
The Middleman has Ida get tickets for the party and Wendy heads home to get her hair done. Lacey has met Mendelson through her mother and wonders if Wendy is on a date with her boss. Wendy and The Middleman arrive at the liner and spot Johnny John and his men. There's no tuba yet, but Wendy spots Lacey and Noser. The Middleman lets Wendy deal with it and Lacey admits she was so impressed by the hairstyling that she hit up her mom's assistant for tickets. Wendy tries to get them to leave and begs them to go, and Lacey reluctantly gives in. However, it's just too late as the liner puts out to sea.
The Middleman and Wendy go tuba hunting and run into Johnny John and his goons. The criminals are no match for Sensei Ping's teaching. The Middleman finds the tuba nearby but Mendelson tasers both of them unconscious and handcuffs them to pipes down below. Mendelson doesn't believe in the curse and leaves with Johnny John. Cecil emerges from hiding and explains that he has arranged the entire thing. Mendelson has assembled everyone with an interest in the Titanic in one place. Cecil used Ida's photo to identify himself as his own great-great-great-great-grandson so Mendelson will have him play the tuba with the band and eliminate anyone who could thwart him.
Lacey and Noser enjoy lobster and Lacey wonders where Wendy and The Middleman are. Noser wonders if she's jealous and Lacey decides to go looking for them and hauls Noser along. Meanwhile, The Middleman tries to text message Lacey to help them, and Wendy wonders why he has Lacey's number. Lacey and Noser arrive and free them, and The Middleman sends them to the other end of the ship with earplugs. Mendelson introduces the band to the guests, while The Middleman and Wendy discover the entire ship is wired for sound. Cecil prepares to play the cursed tuba but The Middleman slugs him. Wendy runs out with the tuba while The Middleman holds off Johnny John and his men. Cecil goes after Wendy while The Middleman speaks over the microphone and tells Wendy to throw the tuba so the water pressure will crush it. Cecil knocks her over the side with a rope and grabs the tuba. The Middleman arrives and eventually spots Wendy and pulls her to safety. They go to the foredeck where Cecil is preparing to play, and Wendy shoots him with a harpoon gun. Man and tuba plummet into the bay together, there to drown for all eternity.
Later, Mendelson announces to his guests that he'll be arrested for larceny and heads off to grab a drink. The Middleman realizes that he can never be with Lacey because of the life he leads. Wendy expresses her regret and The Middleman has one last dance with Lacey as she tells him the ending of Ride Lonesome. He admits she's inspiring but he can't date her because of his job. He bids her goodnight, but Lacey informs him that the movie doesn't end the way you think it's going to happen, but no other ending is possible. They share one last dance as Wendy looks on.