I'm still working on Operation Echo but I'm doing it anyway

What happened after : Zechariah the leader of Echo went and bailed Masterson out of Prison  than recruited him on the Operation cause he told him that he knew more about the Transformers since he faced them three times  and that Zech knew Masterson knew more about the Transformers a lot even if Zechariah does know more and how they function Masterson agrees to join happy to know he'll get to kick the Autobot's butt for kicking his ass three times

Also the Operation Echo might have recruited Meltdown also but I don't know yet