The Cleansing (Mason Walker Book 4) / Alex Howell

Everything seems perfect at Onyx—until they fail their mission.

Roughly one month has passed since Mason joined Onyx. In that time, he saved the President’s family, took his daughter to Stanford, and received orders to take out an Iranian scientist plotting to drop samples of Ebola on Washington D.C. Along with the rest of Onyx, Mason flies over to Tehran to complete what should be a routine mission.

But upon arrival, everything goes to hell. The scientist is nowhere to be seen. The vials are gone. All leads are cold. And, to make matters worse, someone is actively working to sabotage Onyx from within.

With an upcoming presidential election and no leads, the clock is ticking on Mason and Onyx to prevent the greatest biological weapons strike in the history of the United States. And should they fail, it would not just mean the end of Onyx—it would mean the end of the United States.