Prior to the Chimeran invasion, Jonathan worked at the town's coal mines and served as a mechanic for twelve years. During and after the invasion, Jonathan played a key role in maintaining the morale of Mount Pleasant, which its residents quietly continued their way of life. He and his wife ensured that the town remained relatively self-sustainable during this period. However, as Jonathan began receiving the dire news of the bleak situation of the Chimeran War, he began questioning his faith, but nevertheless, he never wavered, and often kept the burden to himself.
However, Mount Pleasant did not escaped from the Chimera's notice. A Chimeran creature named by the town's residents as "Satan" showed up during a church session. Within the first few months of the creature's arrival, hundreds of the town's residents were killed or converted into Grims. Unable to kill the creature and with the town's numbers slowly dwindling, the Roses quickly rallied the town and evacuated them to established safe-zones where Satan could not burrow under.
Sometime between 1954 and 1957, twelve of the town's best hunters volunteered to try and kill Satan, in which a desperate Jonathan agreed to their request. However, less than a day later, only one hunter returned, badly wounded. Now fully resigned to his town's fate, Jonathan and Jean continued their efforts to ensure their town would survive.
Two days before Joseph Capelli and Dr. Malikov arrived in Mount Pleasant, the town's generator malfunctioned. With the town's residents reliant on the generator's heat to stave off the cold. Jonathan decided to fix it himself and he told Jean that he would return in a day. However, he found himself ambushed by a horde of Grims and, unable to call for help, fend them off by himself for roughly two days before Capelli would arrive to save him. During this time, Jonathan discovered the location of Satan and began making plans to kill it after repairing the generator.
Capelli discovered Jonathan on the verge of being overrun and narrowly saved him. Thanking Capelli, Jonathan refused to leave until they killed Satan, and a reluctant Capelli agreed to help him kill it. They traveled to the abandoned mines, where Jonathan's knowledge of the tunnels proved valuable, as the two were able to outrun the feral Chimeran creature. However, Satan ambushed them in a locked room and quickly seized Jonathan, with the intent to consume him. Fortunately, Capelli drove Satan away. Jonathan was left wounded from the attack, and he begged Capelli to kill the creature and leave him behind. Capelli reluctantly consented in which he succeeded in killing the creature and bringing Jonathan back to town.
Sometime after recovering, Jonathan and Jean held up their end of the bargain with Capelli and Dr. Malikov, repairing the town's derelict train to take the men to New York City. The thankful Roses saw them off, and as Capelli and Malikov departed, Capelli requested that the couple pray for them, to which Jonathan readily agreed to do.