On a plane flying from the Philippines to Los Angeles, a Filipina woman named Anita is sitting next to Halley, a Californian. Anita looks at the safety brochure and expresses her hope they won’t have to rely on its information during the flight. Halley sits next to the window and says she likes to read the safety manual to prepare for the worst. 

The pair continue to talk and Halley learns that Anita is an engineer. Halley is a photographer and mountain climber. They both consider the possibility of something going wrong with the flight for a while before falling back into silence, at which point Halley falls asleep. 

When Halley wakes up, the cabin is unnervingly warm and dark. She sees Anita clutching the armrest between them and checks her phone to see that they are only halfway through their flight. Anita points out the lack of sound coming from the engines, which seem to be failing. The pilot alerts the passengers that help has already been sent for so that when they land in the ocean they will not have to wait for long. Anita tells her to climb over and leave her if Halley survives upon impact. 

The plane crashes hard and Halley fights for consciousness as she runs towards the exit. On her way out, she hears a cry — the only human noise she’s heard since the crash — and turns around to rescue a seven-year-old boy named Hilario. Anita is blocking her way to the boy and Halley sees that she is alive, but only barely. Anita tells Halley to save herself, but Halley refuses and unbuckles her new friend. Grabbing Anita and Hilario, Halley takes them both to the surface. 

Halley drags the two people to a nearby shore and they wait for rescuers to come save them. Anita develops a fever and tells Halley that she had planned to die in LA. Halley notices a rash on her neck and Anita tells her she has a plague only one in a hundred people survive and that she’d hoped to spread it to everyone on the aircraft so that they could then spread it in the U.S. Now, with Halley and Hilario still alive, Anita says there’s still hope the disease can spread in the city. Moments later, Anita is dead and Halley is unable to ask her any more questions.

In light of this new information, Halley is struck by how lucky it was that the plane crashed and only the passengers died instead of the other reality in which most of the world’s population died. When Hilario excitedly gestures towards a rescue helicopter, Halley tells him they can’t allow themselves to be rescued. In the sand, she writes the words, “Terrorism—Biowarfare”; “Don’t come” and the helicopter reads the words and retreats. Halley wishes she could tell Hilario the helicopter would be back with miracle drugs, but she knows this is just a fantasy and instead she just hugs the boy.