In 1895, a young immigrant couple finds themselves denied entry into Manhattan due to their illness, consumption. Desperate, they place their infant son in a small sailboat named City of Justice, sending him afloat toward the shores of New York City. Fast forward to 1916, and the baby has now grown into Peter Lake (Colin Farrell), a skilled thief unwittingly raised by a supernatural demon masquerading as the gangster Pearly Soames (Russell Crowe).
As Peter decides to abandon Pearly's gang, he finds himself marked for death. In a fateful confrontation, he is unexpectedly rescued by a majestic white horse that serves as his guardian angel. Although Peter dreams of moving to Florida, the horse persuades him for one final heist at a mansion inhabited by Beverly Penn (Jessica Brown Findlay), a young woman suffering from consumption. Severely weakened, Beverly often sleeps outside in a tent during the harsh winter chills, her father Isaac (William Hurt) and younger sister Willa away from home.
When Beverly stumbles upon Peter in the act of robbing her home, he confesses his desire to forsake thievery. Rather than fear him, Beverly offers to make him a cup of tea, leading to a profound connection and a blooming romance. Meanwhile, Pearly, sensing a spiritual significance in Beverly to Peter’s fate, plots against them. After a narrow escape from a deadly encounter, Peter takes Beverly to the tranquil Lake of the Coheeries, a place where Pearly’s reach ends, allowing Peter to meet her family and earn their trust.
During a serene walk, Beverly shares her belief that everyone harbors a miracle within and that they are destined to become stars in death. Meanwhile, Pearly, undeterred, seeks assistance from Lucifer (Will Smith) to infiltrate their safe haven, yet his request is rebuffed. At a lavish ball, a disguised angel surreptitiously poisons Beverly’s drink. Later, under the enchanting glow of her tent, they share a tender moment, culminating in a tragic turn as she succumbs to the poison coursing through her veins. Grief-stricken after her funeral, Peter returns to the city, only to be ambushed by Pearly and his men on the Brooklyn Bridge.
In a moment of sacrifice, Peter commands his noble steed to flee to protect it, but Pearly violently forces Peter off the bridge. Miraculously surviving, Peter wanders the city for the next hundred years, suffering amnesia while drawing chalk sketches of a red-haired girl. In 2014, the now 119-year-old, yet still youthful Peter encounters a spirited young girl named Abby and her mother Virginia Gamely. In his quest for identity, he rediscover the cherished sailboat's nameplate, City of Justice, as well as the Theatre of the Coheeries, established by Isaac in honor of Beverly.
As he visits the archives, Virginia aids him in piecing together his fragmented memories. During a heartfelt dinner with the Gamelys, he learns Abby has been diagnosed with cancer. Awash with realization, Peter understands that Abby, with her red scarf and hair, is the new miracle he must save, replacing his earlier belief that it was Beverly. Meanwhile, Pearly learns of Peter's return and is enraged upon discovering that Peter was indeed Beverly’s miracle, allowing him to elude death.
With vengeance in his heart, Pearly demands a mortal duel, which Lucifer permits. As Pearly's men lay siege to Virginia's home, Peter and Virginia, along with Abby, take refuge on a rooftop. The noble horse carries them toward the safety of the lake, only for Pearly, now mortal, to pursue them. A fierce battle ensues, and just as defeat seems imminent for Peter, a divine light guides him, allowing him to plunge the City of Justice nameplate into Pearly, who disintegrates into snow.
With Pearly vanquished, Peter rejuvenates Abby with a gentle kiss, saving her from the brink of death. Having paid respects at Beverly's grave one last time, Peter ascends on the majestic horse, disappearing into the stars as Willa, now elderly, witnesses his celestial journey.
