In the online game "Planet," there is a powerful team of four players. This team goes by the name "The Akabane Family," and its members are a pseudo-family that only exists in the game. Although they aren't aware of it, these four players are actually a broken family in real life. A shut-in older brother. A high-achieving younger brother. A father who is not respected by his own children. A mother who neglects her own household. They do not know the warmth of family. They also don't know that the warmth of their online family is only a passing feeling. And most of all, they don't know they are a real family. Centered on the deeds of the Akabane Family in the online game "Planet," the story features battles against monsters, clashes with other guilds, and the machinations surrounding "Black Bird," the final objective of the game. The tale takes a major turn as it entangles the real world and this real family.

Like many hardworking members of the workforce, Kuroto Nakano is perpetually stressed out by his job. Still, since he lives alone, he must carry on to sustain himself. Little do humans like Kuroto know, this stress takes the form of darkness residing within a person's body and will bring one's life to ruin. Fox deities can see this darkness and have the duty to save people before it is too late. To help rid Kuroto of his stress, Senko-san, an eight hundred-year-old foxgirl, volunteers to take care of him, and will do everything she can to ease the tension in his weary soul. [Written by MAL Rewrite]

Makoto and Yura Onoda are a newly-wed couple with zero sexual experience. Yura is a shy and naive 25-year-old woman whose good looks grab men's attention, something that she dislikes because she gets embarrassed very easily. Her husband Makoto is of the same age, but as opposed to his wife, he loves having dirty thoughts about other women. Physically though, Makoto is truly faithful to Yura. Both of them may be virgins, but now that they are married, they are ready to dive into the world of sex, "practicing" as often as possible. However, the world of sex is complex, so they need all the help they can get to find their way through it. Thankfully, their friends, acquaintances, and porn media lend them a helping hand.

A summary of season one of Tensei shitara Slime Datta Ken with some extra content leading into season two.