First episode of a Japanese anime called
High Rise Invasion on Netflix. A teenage girl - the Japanese do love their teen girls in school uniforms

- suddenly finds herself in a weird world composed entirely of linked skyscrapers with no way down to the ground, where people are hunted by mask-controlled stalkers trying to kill them or, preferably, force them to kill themselves. Never seen an anime before, very weird but pretty compelling so far. I'm intrigued.