Cassie opens her apartment door expecting the hallway and instead sees a rainy Venetian street outside, complete with the bakery she remembers from her trip. Stunned, she calls Izzy over, and they both struggle to process the impossibility as dawn light and damp air spill into their New York apartment.

To test whether it is real, Cassie reaches her hand through the threshold and feels cold air and raindrops, then pulls back to show the wetness on her skin. Izzy, frightened and skeptical, also puts her hand through and confirms she can feel the cold and rain too, making it clear the doorway is not a hallucination limited to Cassie.

Cassie wants to step through, driven by wonder and a need for certainty, but Izzy warns her about getting stuck in Venice without shoes or a way back. Izzy takes photos and a short video of the doorway and Cassie leaning into it; when Cassie pushes further by poking her head out, Izzy panics and yanks her back.

Izzy slams the door shut, and when she reopens it, their normal hallway has returned. They review the recorded proof on Izzy’s phone, then Cassie realizes she has been holding John Webber’s book the whole time and notices it feels warm and heavier.

Cassie concludes the Book of Doors caused the shift because she had been thinking intensely about Venice while holding it. When she flips through the pages, a sketched doorway illustration has changed to show the same Venetian street they saw, replacing an earlier image Cassie remembers, suggesting the book adapts to the destination in her mind. Izzy challenges Cassie to repeat it, and Cassie decides they should get coats (and Izzy should use the bathroom) before trying again.