Mike Thompson is a Fighter in the 2nd Massachusetts Militia Regiment. His son was harnessed.
When Hal arrived at the 2nd mass's new base he asked Hal if Hal had seen his son Rick, but Hal couldn't give him a straight answer. When Hal Mason was telling Cpt. Weaver that Click was killed and excluding him Tom Mason's team was being held hostage by John Pope and his outlaws in exchange for their weapons and food. Weaver agreed to the exchange, and he ordered Hal to be guarded from going back to the building where he was captured at, but he decides to let Hal, against his orders go back with Anne Glass and makes it look like Hal stole his rifle and barricaded him in a closet; luckily Weaver falls for this and lets the matter go, without retaliation. ("The Armory")
While on a mission to retrieve Ben from the alien's capture, Mike spots his son, Rick . On an impulse, Mike shouts out for his son, rather than going in covertly, as was the original plan. This shouting sacrifices the original objective, which was to save Ben, but Mike does manage to retrieve Rick. The aversion from the plan also causes Hal Mason and Karen Nadler to become captured by the guarding mechs and skitters . Back with the 2nd Mass , Dr. Michael Harris performs an experimental harness removal procedure on Rick while Mike is at his side, worrying and crying.(Prisoner of War)
He is still sitting by his son's side waiting for his son Rick to wake up. When Rick does Rick asks who he is and he says “I’m your father” after this he realizes where the skitter is and confronts he decides to torture the being for information however all doesn't go well as he put his gun in the skitters mouth and knocks it out Michael Harris and Anne Glass arrive and everyone except Harris are unhappy with him. Harris tells him "if you put a gun in the skitters mouth don't hesitate to pull the trigger" making Anne very mad at this. When the skitter wakes up he realizes Rick is in the same room as the skitter, Tom Mason, Harris, Anne, and Mike arrive. Rick has put on the harness to try to translate for them what the skitter is trying to say. Mike pulls off the harness right in front of the skitter making the skitter even more mad and plus he could have been the one to kill his son.(Grace)
Luckily his son survived he was present as Michael Harris was being attracted by the captive skitter he tried to help Harris but it was too late .(Silent Kill)
He, Weaver, and Tom tracked down a 2nd mass family to get back the antibiotics the family stole they were unable but Clayton arrived and saved the day and Weaver, Him and Clayton appeared to be old friends he was among the security escort that escorted the children of the 2nd mass to the 3rd mass base on what Terry Clayton wanted along with 4 others. (Sanctuary (Part 1))