Since a young age, Kazuhiro Kitase (the dude) has loved sleeping -- because in his "dreams" he travels to another, fantasy-style world. He's able to bring with him bentos (that he leaves by his bed) and not really anything else and his "body" in the other world started as a young child and is now more or less like a teenager, though in the real world he is out in the workforce and in his mid-twenties. When he "dies" in the alternate world, he just finds himself back at home in Japan. He's never questioned it much, since it's been this way since he was young, but it seems like he assumed it was some kind of rich dreamworld.
In the fantasy world, he has a friend, Marie, an elf wizard that he likes to hang around with. But then, one day, they are both killed by a dragon, though Kazuhiro protects her as the fire envelops them. When he wakes up back in Japan, he's very startled to discover a (naked) Marie in bed with him. That's when he realises it isn't just a very realistic dreamworld; it does exist. Why he goes back and forth isn't really explained (at least so far; I'm in episode 8) or why anyone there with him when he falls asleep and/or dies returns with him, but it's not really necessary.
Marie then begins to accompany him back and forth (and later, the avatar of the dragon does as well). So the show is kinda like an isekai but not at the same time. There's cooking related stuff as Marie (and the dragon lady) discover the joy of Japanese food and also just Japan in general, but then it's balanced with their adventuring in the "fantasy" world.
I like the set up. I like the characters. The two main characters are obviously destined for some romance, but it's very sweet and even though big busted dragon lady appears and an old childhood friend, it's NOT a harem (childhood friend is even married!). All around, I'm finding this one charming and a big enough departure from standard isekai that it's quite enjoyable. Will update after the end of the season.
