For thirty-six nightmarish hours, the Carnival Horizon sailed on like nothing had happened. Children shrieked down the waterslides, retirees clinked piña coladas at the RedFrog Rum Bar, and a 16-year-old boy walked the Lido Deck knowing his stepsister’s corpse lay wedged beneath a mattress just four decks below.

While the rest of the ship partied into the early hours of November 8, T.H. – the 16-year-old stepbrother now at the center of the FBI investigation – allegedly did the unthinkable: after strangling 18-year-old Anna Kepner in a 90-second blackout of rage, he dragged her 105-pound body across the carpet, folded her like a doll, and shoved her under the lower bunk. Then he draped the ship’s teal blanket over the edge so it hung to the floor, hiding the horror from anyone who walked in.

He even tucked two bright-orange life vests on top of her, “so she wouldn’t be cold,” according to a redacted statement he reportedly gave a child psychologist in Miami.

But the most stomach-churning detail is what he did next: he went next door and climbed into bed with his 9-year-old half-sister, who had been moved to the parents’ cabin because of a stomach bug. When the little girl woke up at 3 a.m. asking where Anna was, T.H. allegedly whispered, “Shh. Anna’s just sleeping in our room. Don’t wake her, she’s really tired.”

He then lay awake, staring at the ceiling, until sunrise.

By breakfast, the family’s group chat was buzzing with fake normalcy. Shauntel Kepner, the stepmother, posted a smiling selfie on Facebook with the caption “Last sea day vibes!!” – geotagged on the Horizon at 8:14 a.m., less than nine hours after Anna took her final breath.

Meanwhile, Anna’s real mother, Lisa Wright, 400 miles away in Titusville, had no idea her daughter was already gone. David Kepner, Anna’s father, allegedly told the rest of the family to “keep it together” and not ruin the cruise for the younger kids. Sources inside the investigation say he instructed T.H. to “act normal” and even took him to the buffet for made-to-order omelets that morning.

Security footage is devastating: at 9:27 a.m., T.H. can be seen on Deck 9 holding a plate piled with pancakes, laughing with his 12-year-old stepbrother while, four doors down, Anna’s body was beginning to cool beneath the bed he’d turned into a tomb.

It wasn’t until 11:17 a.m. – when a steward named Maria let herself in to deliver the daily Fun Times newsletter and saw a pale hand protruding from under the blanket – that the façade cracked.

Maria’s scream echoed down the entire corridor.

Within minutes, ship security sealed the hallway. T.H. was pulled from the teen club’s dodgeball tournament and taken to the medical center “for anxiety.” There, under the guise of a panic attack, he allegedly asked a nurse, “If someone dies on a boat, do they just throw them overboard like in the movies?” The nurse immediately flagged it to the captain.

By 2 p.m., as the ship approached Miami, the family was confined to separate staterooms. David Kepner reportedly begged officers to let them “handle it quietly back home.” Shauntel was photographed on the balcony sobbing into a towel while on the phone with her attorney. The younger children were moved to the kids’ club under supervision and told their big sister had “fallen really sick.”

When the Horizon finally tied up at Terminal F, the disembarkation was chaos. Thousands of passengers streamed off cheering about their vacation while FBI agents in plain clothes waited at the gangway. T.H. emerged last, pale and shaking, wearing the same gray hoodie from the night before. Instead of walking down the ramp, he was loaded onto a stretcher – not because he was hurt, but because he had begun clawing at his own arms and screaming Anna’s name the moment he saw land.

He was rushed to Nicklaus Children’s Hospital under federal hold. Doctors there diagnosed an acute psychotic break. Sedated and restrained, he reportedly spent the first 48 hours repeating one sentence on loop: “I just wanted her to stop laughing at me.”

Back in cabin 9423, forensic teams worked through the night. They found Anna’s phone cracked on the floor, its final photo a selfie of her smiling in the cabin mirror at 11:29 p.m. – just minutes before T.H. entered. The last text she ever sent was to her best friend back home: “Kinda creepy being alone tonight but it’s fine, love you!!”

Investigators also recovered a single purple fingernail embedded in the carpet – torn off during her struggle – and a smear of blood on the underside of the desk where her head struck as she fought.

Carnival has now quietly offered the Kepner-Wright family a full refund and $5,000 in future cruise credit – an insult that Lisa Wright says she will frame and hang in Anna’s bedroom “as a reminder of how little a little girl’s life is worth to them.”

Tonight, as another Carnival ship pulls away from Miami with lights blazing and music thumping, Anna’s bedroom in Titusville remains exactly as she left it: cheer uniform draped over the chair, college acceptance letter on the dresser, a half-finished iced coffee sweating on the nightstand.

And somewhere in a locked adolescent psych ward, a 16-year-old boy who once shared Christmas mornings with the sister he murdered now draws picture after picture of stick-figure girls with red X’s over their necks.

The cruise was seven nights.

For Anna, the nightmare will never end.