Momo believes in ghosts but rejects aliens; her schoolmate Okarun believes in aliens but rejects ghosts. Each challenges the other to visit a place associated with the thing they refuse to accept. The argument becomes a shared emergency when both encounters prove more dangerous than either expected.
Momo’s grandmother Seiko gives those discoveries an experienced counterpoint. A spirit medium who understands protective barriers, she can offer rules where the teenagers have mostly brought guesses. Her involvement connects the strange events outside school to a home where someone already takes the supernatural seriously.
The pair’s disagreement leaves them with different pieces of the same problem: Momo has encountered the aliens Okarun insisted were real, while he has met the spirit she believed in. Neither can dismiss the other’s account so easily afterward. Their exchanges now carry the awkwardness of needing help from the person each had just tried to prove wrong.