Tengoku dai makyo

The story is set in two distinct worlds. Tokio lives with other children inside a world surrounded by a beautiful wall,

but one day he receives a message that reads,

“Do you want to go outside?” Meanwhile,

a boy named Maru travels with an older woman,

eking out a meager existence in a ruined world as they search for “paradise.”
Note: Winner of Kono Manga ga Sugoi! 2019 Award in Male Readers category.