Karl Schneider, writer for the Berlin Allgemeine, is suspected of being a German/Soviet double agent. While D-Agency searches for proof of his espionage activities, Schneider suddenly dies under mysterious circumstances. Lieutenant Colonel Yuuki sends his men on individual missions in order to uncover the truth.

Hermann Wolff, a Wehrmacht Colonel assigned to German's intelligence agency, the Abwehr, investigates a suspicious train crash on the outskirts of Berlin with his right-hand man, Lieutenant Johann Bauer. Among the belongings of one of the bystanders is one of a spy's standard tools of the trade. When interrogated, its owner claims to have stolen it from a Japanese man named "Maki Katsuhiko..."

Aaron Price, Far East correspondent for the British Times, investigates the true identity of Lieutenant colonel Yuuki, the man rumored to have founded D-Agency. Flipping through the Military Preparatory School's list of past enrollees, his eye is drawn to a boy who passed the entrance exam at the top of his class, but was expelled for violence. His name? Arisaki Akira.

Autumn, 1937. Against the Imperial Army's objections, Lt. Colonel Yuuki establishes the spy training group "D-Agency." The army sends Liuetenant Sakuma to serve as their liason to D-Agency, and he watches the applicants easily coast through the brutal examination process. Not long after, Sakuma is ordered by Colonel Mutou to search the home of a suspected American spy, the Japanophile John Gordon. Disguised as military police, Sakuma leads D-Agency on their first mission.

Touya arrives in Oedo, a Japanese-style castle town within Tokugawa Ieyahsu's domain, and quickly heads to Yae's home. There he meets their servant, Ayane, and Yae's mother, Nanae, before hearing that Yae's father and brother went off to war with Ieyahsu.

After returning from the Kingdom of Mismede, Touya and the others enjoy their daily life. Yet behind the scenes the women battle over the bicycle Touya created! Notice it, Touya! At Sushie's request they head to Mismede and return to find Leen and Paula. According to them, the crystal beast Touya and the others once defeated had appeared in Mismede as well, and Leen struggled to defeat it. So she began to take interest in Touya after he defeated the beast. Acutely interested in the high spec Touya, Leen asks Touya and the others to investigate some ancient ruins, leading to the start of a new adventure! (Made easier with Gate.)

Touya's party heads out for Mismede once more. Then they finally arrive in Mismede's royal capital, Berge. Their party heads to the palace and gains audience with King Jamukha. Then somehow Touya and the King end up doing battle in their fighting arena?! That night a party is held in the royal palace, but a moving stuffed teddy bear appears before Touya when he sneaks out of the reception! The bear leads him to the self-proclaimed 612 year old fairy leader, Leen. Then Touya uses his newly obtained Null magic, Program, to create the handgun Brunhild, and grow even more powerful!

After receiving a huge mansion in place of court rank, Touya and the others begin living their usual dense, thickheaded lifestyle. Then Duke Ortlinde's daughter Sushie joins them. They receive a mission to head all the way to Mismede because she'd like to use Touya's Gate spell for talks with The Kingdom of Mismede. Mismede's ambassador, Olga, her daughter Arma, and their two guards join their traveling group. On their journey they encounter a dragon attacking a village on what should normally be sacred ground! It's Touya vs another world's orthodox dragon! Which party will win...?!

Touya and the others set out to investigate some magic beasts, but it turns out their destination is the castle of a mage who researched slimes, which they'd all been avoiding (though Touya seems excited?) Touya and the others advance to carry out their investigation, but Green Slimes capable of dissolving clothes stand in their way! They climb the staircases to run away from the slimes chasing them, but in their path are Lotion Slimes! The way forward is wet and slick! The way back is slimy and smooth! What was the goal of the research behind this slick and slimy and slime panic?!

Touya is brought to the royal palace by the Duke. There he finds the King, bedridden, on the verge of death after being poisoned by someone... No one knows how to treat it, and many believe there's no hope of saving him. Yet high-spec Touya handles the poison with ease! He saves the King with his super Healing magic, Recovery, and even catches the criminal who poisoned the King quickly, bringing everything to resolution. Meanwhile, after watching Touya's actions, Princess Yumina makes a startling declaration...

Touya and the others head to ruins on a new quest from the Guild to defeat a dullahan. There they encounter the ancient royal capital, abandoned after the capital was moved a millennium ago. After finishing their quest, Touya and the others explore the underground ruins for treasure. Yet what they find isn't a mountain of treasure, but a magic beast made of crystal! No attacks work on its hard body, it absorbs magic, and it even regenerates from wounds. Touya and the rest struggle against such a powerful creature... What on earth is the true identity of such a magic creature?!

While surprised by the differences from his previous world, Touya is growing accustomed to living in the new world with his smartphone. Together, he, Elze, and Linze accept a mission to head to the Royal Capital. Along the way they encounter a young samurai, Yae, who dropped all of her travel coins, a currency in the new world. After treating Yae to sate her hunger, Touya grows worried about his own savings due to how much she eats. Afterward Yae joins their party to repay the favor, and their traveling group encounters Sushie, heiress to a duchy, under attack.

When Touya returns to the mansion, the problem of taking his brides awaits. Yumina and Linze (mostly Yumina) push and push until Touya accepts his engagements. Even Elze and Yae get to join in the polygyny! Hey, are you okay with this, protagonist?!

Before him lies a young girl in white panties. After Touya arrives at the aerial garden, he's greeted by a young girl in white panties, Francesca. She's the keeper of the garden.

After arriving at the beach where the Nilya Ruins lie, Touya and the others take a moment to enjoy the seaside. With so many beautiful girls in swimsuits, Touya's heart is racing!

After dying due to God's mistake, Touya is reborn in another world?! There he meets the twin sisters, Elze and Linze, and starts his new life in another world along with the smartphone he got God to let him use in the new world. Thanks to God's power Touya's a new person with increased abilities and a new talent for magic, so he uses his super convenient smartphone to help defeat beasts, create ice cream in the new world, and start enjoying his newfound life. What will happen to Touya's life as time goes on?!

Touya arrives in Oedo, a Japanese-style castle town within Tokugawa Ieyahsu's domain, and quickly heads to Yae's home. There he meets their servant, Ayane, and Yae's mother, Nanae, before hearing that Yae's father and brother went off to war with Ieyahsu.

After returning from the Kingdom of Mismede, Touya and the others enjoy their daily life. Yet behind the scenes the women battle over the bicycle Touya created! Notice it, Touya! At Sushie's request they head to Mismede and return to find Leen and Paula. According to them, the crystal beast Touya and the others once defeated had appeared in Mismede as well, and Leen struggled to defeat it. So she began to take interest in Touya after he defeated the beast. Acutely interested in the high spec Touya, Leen asks Touya and the others to investigate some ancient ruins, leading to the start of a new adventure! (Made easier with Gate.)

Touya's party heads out for Mismede once more. Then they finally arrive in Mismede's royal capital, Berge. Their party heads to the palace and gains audience with King Jamukha. Then somehow Touya and the King end up doing battle in their fighting arena?! That night a party is held in the royal palace, but a moving stuffed teddy bear appears before Touya when he sneaks out of the reception! The bear leads him to the self-proclaimed 612 year old fairy leader, Leen. Then Touya uses his newly obtained Null magic, Program, to create the handgun Brunhild, and grow even more powerful!

After receiving a huge mansion in place of court rank, Touya and the others begin living their usual dense, thickheaded lifestyle. Then Duke Ortlinde's daughter Sushie joins them. They receive a mission to head all the way to Mismede because she'd like to use Touya's Gate spell for talks with The Kingdom of Mismede. Mismede's ambassador, Olga, her daughter Arma, and their two guards join their traveling group. On their journey they encounter a dragon attacking a village on what should normally be sacred ground! It's Touya vs another world's orthodox dragon! Which party will win...?!