Triangulation

After a recent case with a treacherous client, North and Shaw are ready to go back to work building Borealis Investigations. They're also ready to go back to dodging their feelings for each other, with neither man ready to deal with the powerful emotions the Matty Fennmore case stirred up. Everything is getting back to normal when their secretary asks for help: her girlfriend's boss has gone missing. 

Shep Collins runs a halfway house for LGBTQ kids and is a prominent figure in St. Louis's gay community. When he disappears, however, dark truths begin to emerge about Shep's past: his string of failed relationships, a problem with disappearing money, and his work, years before, as one of the foremost proponents of conversion therapy. 

When Shep's body turns up at the halfway house, the search for a missing person becomes the search for a murderer. 

As North and Shaw probe for answers, they find that they are not the only ones who have come looking for the truth about Shep Collins. Their investigation puts them at odds with the police who are working the same case, and in that conflict, North and Shaw find threads leading back to the West End Slasher—the serial killer who almost took Shaw's life in an alley seven years before. As the web of an ancient conspiracy comes to light, Shaw is driven to find answers, and North faces what might be his last chance to tell Shaw how he really feels.