At the helipad, perimeter lights turn on as Lyra and Grayson arrive. They inspect the bull’s-eye, and Grayson locates a concealed latch. Working together, they lift a heavy concrete disk to reveal a locked metal plate with a narrow two-inch slit at its center. Lyra runs her fingers along the surface and confirms there are no hinges, and they deduce the slit is a keyhole for a sword.

Rohan and Savannah Grayson overhear Lyra and Grayson’s discovery at the helipad. Rohan tells Savannah to stall them while he retrieves their sword. In the library, Rohan scales a bookshelf to reach a hidden longsword. Jameson comes in and confronts him. He voices suspicion of Lyra and asks Rohan to find grounds to disqualify her. Rohan pivots, arguing that Brady Daniels is the larger threat. Jameson also raises Rohan’s rival, Zella, “the Duchess,” who is vying with him for the position of Proprietor of the Devil’s Mercy.

Rohan returns to the helipad, where Savannah delayed Grayson by faking an injury. Savannah inserts the sword into the slit, and they twist the blade to release the lock. They uncover and digitally sign a ledger, opening two more compartments filled with a chemical liquid. From them, each retrieves a charm bracelet and a sword charm as a recorded voice plays a coded message. When Savannah submerges her engraved room key in the liquid, it glows with the Roman numerals VIIIL.

In the stone room, Gigi Grayson presses Slate about Savannah’s connection to Eve. Slate confirms that Eve told Savannah that the Hawthornes, specifically Avery, are responsible for their father’s death. Eve’s phone call draws him away, and he locks Gigi in. 

Gigi seizes a heavy candleholder and ascends a stone staircase, recognizing the building is a lighthouse. Slate intercepts her, explains he staged events to look like an escape, then carries her down and ties her.

Back at the helipad, Lyra and Grayson parse VIIIL as Roman numerals. Lyra senses eyes on her from the ocean and drifts toward the waterline. Grayson follows and messages security to sweep the island perimeter. The helipad lights flicker, and afterward, Lyra finds a single white calla lily placed on a nearby rock.

Brady Daniels arrives at the helipad and works the mechanisms to reach the ledger. Grayson confronts him about his motives and sponsor. Brady notices the calla lily, says it might be for him, and shows Lyra a photo of a girl named Calla. He sidesteps Grayson’s challenge by suggesting Rohan could have left the flower. Before leaving, he quietly supplies Lyra with the key to the Roman numeral puzzle.

Back in the house, Lyra reaffirms that she plays to save her family’s home, Mile’s End. At a large clock, they first set the hands to 8:50 to match VIII and L. When nothing opens, Lyra realizes they must form an L shape with the hour hand on VIII. The clock face opens, revealing metal drawers and a ledger already signed. After Grayson and Lyra sign, two drawers open, and each retrieves a silver box topped with a clock charm.

In Brady’s room, Rohan and Savannah examine their silver music boxes. The mechanisms cycle through songs, including Clair de lune. While searching, Rohan pries behind a mirror and uncovers a second, newer photograph of Calla Thorp. He compares it to the worn photo he previously stole from Brady. Noting that someone has solved the clock puzzle, they look toward the beach and spot an illuminated piano.

Bound by silk, Gigi resolves to free herself. She hops to a stone wall and feels along the surface until she finds a jagged rock. Using the sharp edge, she saws at the silk on her wrists, working through the material in the dark.

In the mosaic ballroom, the marble calla lily inside Lyra’s music box triggers traumatic memories of her father’s death. Grayson steadies her, then gives her space. Alone, Lyra discovers a charcoal drawing Grayson made of her. The drawing gives her the resolve to face her past, and a broken fragment of memory rises: a woman’s voice addressing her.

In the Great Room, Grayson finds a violin and receives a discreet signal from the game makers. He plays the waltz and tango from the music box to test a theory. Lyra enters and admits she is struggling. Acting on instinct, she uses the violin bow to rip the velvet from her music box’s lining. Beneath it, they uncover an etched infinity symbol.

Rohan sits at the moonlit piano on the beach and plays the music box melodies while Savannah writes corresponding letters on her arm. They trade truths about their strained family relationships. Rohan shares that Jameson warned him about a looming threat and asked him to help get Lyra out of the game. When Savannah asks for the Calla photos, Rohan hands them over, and they agree to work the puzzle independently.

Gigi cuts through the silk around her wrists with the jagged rock and frees her ankles. She retrieves the heavy iron candleholder and plans to climb to the top of the lighthouse to break a window, hoping the shattering glass and light will draw help.

On the boathouse roof, Lyra and Grayson search for an infinity symbol in the landscape. They notice intermittent flashes of light, and Grayson leaves to investigate. Eve appears and reveals that she sponsors Lyra, adding that the flashes were a distraction. She offers Lyra $2.5 million and her father’s complete file in exchange for losing the game, ensuring Grayson also loses, and ending their relationship. She also denies sending the calla lily.

Grayson returns and reports that he found no clue at the lights. Lyra conceals her meeting with Eve and says she saw no pattern. Grayson promises to ask his brothers about the lily. Lyra pulls him into a prolonged kiss, but Grayson brings them back to focus on the need to win for Mile’s End, and they recommit to the puzzle.

At the shoreline, Rohan processes a painful memory of being a child in the dark water. Savannah arrives with the solution, and they go to the Great Room. There, she holds Brady’s photographs to the fire, and the heat reveals hidden messages instructing him to obey exactly and ensure the game continues. They conclude that Brady acts on a sponsor’s directives. At midnight, their watches instruct them to put on formal wear and meet at the dock.

In Rohan’s room, his closet opens to reveal formal attire. A purple tuxedo triggers a flashback to his induction into the Devil’s Mercy. Savannah enters, already dressed, and says that Gigi’s betrayal has severed their bond. Moved, Rohan shares that during his initiation into the Devil’s Mercy, stones were tied to his ankles in the water. He cuts the conversation short and changes for the gala.