Ordinary high school student Usato is mistakenly suddenly summoned to another world along with his classmates and student council members Suzune and Kazuki.

Following the discovery of his unique power, Usato has been recruited/abducted into the kingdom's Rescue Team. And he has no idea the hellacious training he's in for!

Usato is quite literally thrown into his next training assignment: surviving the wild woods known as the Darkness of Llinger until he can slay its most fearsome inhabitant.

As the demon threat looms over the kingdom, Captain Rose decides it's high time for Usato to get a taste of what a healer's job is like on the battlefield. She tests his resolve, both mentally and physically.

Usato gets drafted to help Inukami on a training expedition outside the castle to get some real combat experience. He's only supposed to be there in case things go wrong, but things definitely go wrong!

Captain Rose receives grim news from the king: invasion is imminent. Can she rally her small team before all hell breaks loose? Moreover, is Usato even ready for war?

Now that Usato, Kazuki, and Suzune all know that war is upon them, they must each steel themselves to face the battle ahead—because the invasion is coming, ready or not!

A look back into Rose's past as a new battalion commander and her relationship with her old team. Just who were they? And where did things go wrong...?

Usato, Kazuki, and Suzune finally set foot on their first battlefield. The conflict is harrowing enough as it is for all of them, but reports of a terrifying foe among the demon army have Usato in particular shaking in his boots...

Usato's first battle quickly turns into a waking nightmare when he realizes his friends are tangling with their fated foe, the Black Knight. Can he make it in time to save them?

Now that Usato's first clash with the Demon Lord's army is over, he's going to have to deal with the aftermath—including a prisoner of war.

With Usato's first battle behind him, it's time to face the path ahead. He receives a special diplomatic quest from the king as well as a personal request from the mysterious fox girl, both of which will take him on a winding journey to new lands.