While recovering from a severe injury, Wisting receives an anonymous letter in the mail. The cryptic content leads Wisting to suspect a possible injustice in an old murder case where a 17-year-old girl was killed, and her ex-boyfriend was convicted.

A breakthrough in the case takes Wisting to Vilnius for a meeting with Interpol investigator Harriet Dunn. What is meant to be a simple questioning of a suspect becomes far more complex for both of them - both professionally and personally.