Chaos Hangs in the Air... Everything seems to be going wrong as Arata's client, the Japanese government, fumbles in their handling of the job's agreements. As conflict begins to heat up within the country, Arata is forced to take to the bustling streets of Tokyo and face off with the terrorist cult. Will he and the kids be able to survive in this unfamiliar battlefield?

The life of a private mercenary is far more grueling than he could have ever imagined! Our hero Ryouta Arata is an otaku who's just lost his job after the dissolution of his company. Unwilling to return to his old NEET ways, he applies online to a private military security company, thinking the benefits to be promising. After what appears to be a baffling test, he's assigned to be an "operator of operators" and begins his training in a foreign country.

Foreign Shore Trouble... After leaving Japan, Arata ends up drifting to Thailand. His fame has continued to grow, and now there is no one in the mercenary world who hasn't heard of the famous Headmaster. However, all he wants is to find a place where he can raise his children in peace, and not have to send them to war just to earn a living. Will this south asian nation finally provide him with an opportunity to do so, or will he be forced to fight again?

Pushing foreign borders... In accordance with his sponsors' wishes, Arata finally makes a move against the Chinese army. Initially, things are going well, and he's able to recapture multiple villages without any casualties. But while it seems his momentum is unstoppable, Arata soon discovers this conflict is far more complicated than he originally thought...

With Arata's training camp now complete, he's sent off to his first official post as a PMSC employee. Determined to atone for the sins he unwittingly committed, he tackles his new job with zeal, trying his best to keep as many people alive as possible. Unfortunately, the mercenary life is a harsh one, and the darkness within PMSC runs far deeper than Arata could have ever imagined. Can he stay true to his ideals despite coming face-to-face with the horrors of war?

Arata had come to accept the weight of his life-or-death decisions, but with his own life on the line for once, will he be able to keep his cool under fire? Even as he faces this new challenge, his mastery of battlefield tactics has caught the attention of a mysterious group of combatants in this endless war. Will he live to fight another day?

Reunions abound... Arata succeeds in securing more funds from his sponsors and is now able to procure the anti-aircraft weapons he so desperately needs. However, before he can, he encounters previous friends and enemies alike. Laying his old grudges to rest, Arata then moves forward with fighting back against China's aerial forces. No amount of victories will return the lives he's already lost, but he can't afford to stop in his tracks or risk incurring more casualties.

Going on the Offensive... With the Chinese Army presenting an overwhelming difference in firepower to his own forces, Arata employs guerrilla tactics to successfully take out a key refueling base. However, this enrages the Chinese Army more than expected, leading to an air strike against Camp Hakim in retaliation. With the Burmese Army still disorganized and his sponsors unwilling to lend further aid, the only person Arata can rely on to get them out of this mess is himself.

The battle in Myanmar rages on fiercer than ever before. China has deployed their helicopters and drones, while Arata’s allies, the Burmese Army, turn out to be far less reliable than he'd hoped. It will take the full extent of his considerable wit to continue winning his battles and keeping his kids alive. Fortunately, by rescuing the nearby villagers from their own government's tyranny, he may have inadvertently created the perfect strategic opportunity for himself.

The final push... Once a former NEET, Arata Ryouta is known worldwide as the legendary mercenary leading a tiny platoon of child soldiers against the Chinese army. With only 3,000 troops under his command, he's succeeded in multiple campaigns against a force tenfold his own. Respected by his allies and reviled by his enemies, Arata has one last marginal operation to complete before his story comes to a close.