"First published in Japan in 2020 by Kodansha Ltd., Tokyo as Mizutamari ni ukabu shima, volume 1"--Colophon
Summary
"Minato's tiny apartment might as well be on a deserted island. Despite being in elementary school, it falls on his shoulders to care for his little sister Nagisa, who never stops asking when their mother will make one of her infrequent visits home. One day when she stops by, their mother takes them to an amusement park, only to give Minato cash and leave them at the Ferris wheel. However, as they reach the top of the ride, [lightning] strikes their car-- but what Minato finds when he awakens is not the grim tragedy he expected ..."--Page 4 of cover