Pip cannot sleep before school because the anonymous warning text confirms that the earlier note in her sleeping bag was not a joke. Since Pip has tightened access to her research after the camping trip, Pip concludes that the sender must be someone connected to her investigation: either Ravi or someone Pip has interviewed.

Pip tries to reply to the message, but the response fails. After researching the issue, Pip learns that anonymizing websites and apps can send texts that cannot be answered or traced, leaving the sender effectively nameless as Unknown.

Pip considers whether Unknown might be Andie Bell's real murderer and whether the threat is meant to make Pip believe Unknown can reach her too. Pip decides not to go to the police because Pip lacks hard evidence, possessing only informal statements and a list of seven persons of interest with possible motives.

Because Pip needs tangible proof, Pip fixes on finding Andie's burner phone as the key to moving the case forward. Pip resolves that she will stop only once the truth is exposed and Unknown is no longer hidden.