Vince and Dave are fishing when they notice a corpse in a nearby dinghy. Audrey and Nathan are called in to investigate. The dead man has no ID, but looks extremely
elderly and has a tattoo of a circular maze on his left arm. Audrey tries to ask Vince and Dave about Lucy, but they awkwardly change the subject. The harbor mistress, Beatrice Mitchell, arrives and shows off her newly adopted baby son, Ben. The normally gruff and withdrawn Nathan giggles and coos over the baby, creeping Audrey out. Beatrice reports the dinghy as stolen. Audrey decides to question Duke, who has turned the restaurant Bill McShaw had sold him last episode into a bar and grill, The Grey Gull. Nathan doesn't want to come due to his grudge against Duke.
At The Grey Gull's grand opening, Audrey tries to find someone who can identify the dead man, but everybody brushes her off until she offers to buy everyone drinks. Duke then invites her to have a drink and she agrees, and he tries to get her to relax and join him for a home cooked dinner in a week. They talk with Nora, the bartender, and notice a local man, Joe Campbell, making out with an attractive stranger.
Later, Nathan and Audrey investigate tattoo parlors. Nathan says that judging by the dead man's equipment, he's a lobster poacher. One artist recognizes the maze tattoo, claiming to have designed it, but says that he never put it on any old men.
Eleanor, the EMT and town coroner, talks with Audrey at a tennis court. She's examined the body and says that he is supposed to be in his 30's. Audrey wonders what could speed up the aging process. Eleanor says the body had no drugs in its system. An elderly man staggers out and collapses, dead. They check his ID, he's Joe Campbell.
Nathan and Audrey go to The Grey Gull. Duke doesn't know who the woman Joe was with is. Audrey assures that she will meet Duke for dinner as promised. Nora says that the woman's name is Helena. They call in Dave to do a composite sketch based on Audrey's description. Nathan checks Joe's record and finds that he had a history of poaching.
The officers speak to Beatrice. She claims not to recognize Helena based on her sketch. She's shocked to learn that Joe is dead. Her baby nanny Abby walks in. Beatrice explains that she's going on maternity leave. When the officers leave, Beatrice and Abby discuss that they have to be careful because the police are on to Helena.
The first dead man has been identified, Phil Reiser. Nathan and Audrey stake out his partner's place. Duke calls, disappointed that Audrey has stood him up. She apologizes for forgetting. Phil's partner, James Wardel arrives, and they question him. He explains that two Fridays ago, Phil had a one night stand with Helena. The next day, while they were lobster poaching, Phil started rapidly aging. When he died, James panicked and abandoned the dinghy, fearing he would be arrested both for poaching and the suspicious circumstances. Audrey realizes that Joe went out with Helena one Friday ago, and now today is Friday.
At The Grey Gull, Duke is sad over Audrey standing him up. Helena walks up and flirts with him.
The next morning, Duke wakes up in his bed on his boat alone. He gets dressed and walks out. He notices Beatrice and Abby walking past.
Nathan and Audrey do some research and discover a similar case from 1954. Alexandra Leidner slept with a man who rapidly aged, while she gave birth in a few days. She died in childbirth. Duke calls them and says he met Helena. They go to his boat and find he's rapidly aging. Duke explains that Helena seemed to mesmerize him and they slept together. Duke refuses to go to the hospital, as they wouldn't know how to treat him. He says Beatrice and Abby are their only leads, and insists on coming with them.
At Beatrice's house, Abby tries to stop them from coming in, but they barge in. Inside are several cribs and women's dresses. Duke recognizes Helena's dress from last night and the one from when she was with Joe. They find a birth certificate and find that Beatrice's real last name is Leidner. Abby admits that Beatrice is Alexandra Leidner's granddaughter and Beatrice transforms into Helena every Friday.
The four of them go to Beatrice's hiding place, a lighthouse. Duke is now elderly. The officers kick the door in and find a very pregnant Beatrice and two more babies, each a week old. Beatrice apologizes, and says that she has no control over Helena's actions. Beatrice's water breaks and Abby administers to her. Duke walks outside and collapses. Nathan runs out to help him.
As Abby works to deliver the baby, Audrey questions Beatrice, trying to find a clue to save Duke. Beatrice says that her Trouble triggered two weeks ago, when she got upset after her ex-husband, who had started a family, taunted her over being barren. Outside, Duke says that he doesn't want to die all alone. Nathan admits that he doesn't hate Duke enough to want him dead.
Audrey pursues the matter and realizes that Joe Campbell died one day later than Phil, and pieces together that he died when Beatrice held the baby. Duke stops breathing and Nathan attempts CPR.
Once Beatrice gives birth, Audrey suggests that if the father holds the baby first, it will undo the aging process. Abby and Beatrice agree, and Audrey takes the baby to Duke. But when she approaches with the baby, Duke screams in pain. Audrey backs away, and he starts feeling better. Audrey and Nathan figure that they have to keep the baby away from both
parents to save Duke. Audrey drives away with the baby and puts her up for adoption.
Later, Audrey meets Duke, who has gone back to normal, and tells him that Beatrice's third child, Jean, is his. He's shocked, and Audrey shows him a picture of Jean. He's amazed to realize that he has a daughter, but Audrey warns him that he can never meet her or he will die. He says he can live with that, and Audrey says that she took the photo as a favor to Jean. Jean's lucky, unlike Audrey, who was an orphan and never saw her own baby pictures. Duke walks away shocked, and runs into Nathan. Nathan stares at him for a minute and leaves.
Later, Abby cares for the two babies and locks Beatrice in the lighthouse. Beatrice transforms into Helena, who realizes that she's trapped. Unable to go out and seduce men, she decides to look out across the town.