A message appears beside a body.
I AM NOT HAPPY.
At first, the murder looks random. Brutal, but ordinary for a city like Seattle.
Then another body is found.
Same message.
Same chilling precision.
Detective Ethan Cole quickly realizes the victims share a disturbing connection: years ago, they were all part of a controversial psychological research project known as The Happiness Index Study—an experiment designed to measure how much pressure it takes to break the human mind.
But someone isn’t trying to break people anymore.
Someone is finishing the experiment.
As the murders begin to follow the exact stages of the original study, Cole and his partner Maya Torres race to uncover the truth before the final phase begins. Because the killer understands the experiment better than anyone.
And every clue suggests something far more terrifying than revenge.
The experiment didn’t end.
It created something.
Now the survivors are disappearing.
The researchers are dying.
And the final stage is about to begin.
But this time, Detective Cole may not be investigating the experiment.
He may be part of it.
