With Molly Murphy’s wedding to NYPD Captain Daniel Sullivan quickly approaching, the Irish P.I. heads to the Westchester County countryside,where Daniel’s mother can counsel her on a bride’s proper place. Surprisingly, Molly seems to be agreeing with her future mother-in-law’s advice. Molly promises to leave her detective work behind and settle down after becoming Daniel’s wife…but she isn’t married yet. So when she gets word of a possible case, Molly sneaks back into the city to squeeze in a little more sleuthing before the wedding bells can ring.

Molly Murphy - now Molly Sullivan - is a year into her marriage, expecting her first child, and confined to the life of a housewife. She’s restless and irritable in the enforced idleness of pregnancy and the heat of a New York summer in 1905. So when a trip to the post office brings a letter addressed to her old detective agency asking her to locate a missing Irish serving maid, Molly figures it couldn’t hurt to at least ask around, despite her promise to Daniel to give up her old career as a detective. On the same day, Molly learns that five babies have been kidnapped in the past month.

Irish immigrant and private detective Molly Murphy is thrilled to have a ticket to see world-famous illusionist Harry Houdini. But before he can even take the stage, the opening act goes horribly wrong—and the sensational Signor Scarpelli’s lovely assistant is sawed in half. In the aftermath, Scarpelli accuses Houdini of tampering with his equipment. Who else but the so-called Handcuff King could have got a hold of his trunk of tricks, which he keeps under lock and key?

Molly and Daniel Sullivan are settling happily into the new routines of parenthood, but their domestic bliss is shattered the night a gang retaliates against Daniel for making a big arrest. Daniel wants his family safely out of New York City as soon as possible. In shock and grieving, but knowing she needs to protect their infant son, Liam, Molly agrees to take him on the long journey to Paris to stay with her friends Sid and Gus, who are studying art in the City of Light.

It’s wintertime in New York, and for the first time since Irish immigrant Molly Murphy started her early-twentieth-century detective agency, she is completely snowed in with work. While she’s proving to be quite the entrepreneur and is very much in demand by some of Broadway’s brightest stars and Fifth Avenue’s richest families, she has to grudgingly admit that if she’s going to work more than one case at a time, then she’s going to need some help.

It's Christmastime in 1905 New York City, and for once Molly Murphy Sullivan is looking forward to the approaching holidays. She has a family of her own now: She and Daniel have a baby son, and 12-year-old Bridie is living with them as their ward. As Molly and the children listen to carolers in the street, they hear a lovely voice, the voice of an angel, and see a beggar girl huddled in a doorway, singing "Away in a Manger". Bridie is touched by the girl's ragged clothes and wants to help her out if they can.

Molly Murphy Sullivan's husband, Daniel, a captain in the New York City police force, is stumped. He's chasing a murderer whose victims have nothing in common - nothing except for the taunting notes that are delivered to Daniel after each murder. And when Daniel receives a note immediately after Molly and her young son, Liam, are in a terrible train crash, Daniel and Molly both begin to fear that maybe Molly herself was the target.

Molly Murphy's beau Captain Daniel Sullivan may be out of jail on bail, but he's still a ways from clearing his name, and his foul mood has Molly in search of a little breathing room when providence steps in in the form of a proposition from New York City's renowned theatrical impresario Tommy Burke. America has been very good to Tommy, and now that he's getting on in years, he'd like to pass some of that good fortune on to his family back in Ireland.

In turn-of-the-century New York City, Irish immigrant Molly Murphy is contemplating giving up PI work for something a little less complicated, less exciting. Molly has had quite enough excitement recently, thank you very much. Especially from the handsome but deceptive NYPD captain Daniel Sullivan, whom she'd like to avoid completely. But when Daniel is accused of accepting bribes and lands himself in the Tombs, the notorious city jail, he begs Molly to help prove he was framed, and after everything they've been through, she cannot turn him down.

Molly Murphy Sullivan's husband, Daniel, a police captain in turn-of-the-century New York City, is in a precarious position. The new police commissioner wants him off the force altogether. So when Daniel's offered an assignment from John Wilkie, head of the Secret Service, he's eager to accept. Molly can't draw any details of the assignment out of him, even where he'll be working.

Semi-retired private detective Molly Murphy Sullivan is suffering from depression after a miscarriage following her adventure in San Francisco during the earthquake of 1906. She and her husband, Daniel, are invited for Christmas at a mansion on the Hudson, and they gratefully accept, expecting a peaceful and relaxing holiday season. Not long after they arrive, however, they start to feel the tension in the house's atmosphere.

Molly Murphy is starting to think the cards are stacked against her. She's determined to be a private detective, but hampering her investigations is the fact that she's finding many places in turn-of-the-century New York City where women are not welcome, something that's as frustrating to her fiery Irish pride as it is to her rapidly emptying pocketbook. Then two business opportunities pop up simultaneously. An aristocratic family in Dublin fears their daughter has fled to the New World with her unsavory boyfriend, and they hire Molly to track the two down and send the young woman back home.

Molly Murphy has finally begun to forget the unpleasant murder of a would-be rapist back in Ireland, not to mention her investigation into the murder of a fellow recent Irish immigrant, and is finally free to begin her life in New York City. Given her experiences so far in the New World, Molly has decided that her first order of business is to become a private investigator, a people finder of sorts, working for families in Europe who've lost touch with relatives in America.

Molly’s policeman husband, Daniel, is late returning home. He comes with a tale to tell: There was a murder on Ellis Island that day, and the main suspect is the spitting image of Molly. The circumstances are eerily similar to when Molly herself arrived on Ellis Island, and she can’t help but feel a sense of fate. Molly was meant to be there that day so that she can clear this woman’s name. 

Molly Murphy always knew she'd end up in trouble, just as her mother predicted. So, when she commits murder in self-defense, she flees her cherished Ireland, under cover of a false identity, for the anonymous shores of late 19th-century America. When she arrives in New York and sees the welcoming promise of freedom in the Statue of Liberty, Molly begins to breathe easier. But when a man is murdered on Ellis Island, a man Molly was seen arguing with, she becomes a prime suspect in the crime.