When Yuki Kai went to pick up her 14-month-old son, Kento, from a nursery in Tokyo after his nap time, she found him dead.

That was on March 11. Since then, Kai has found herself fighting for answers as to why he died, with little help from the nursery or from the state.

Kai, a 39-year-old medical interpreter from Chiba Prefecture, has found it excruciatingly hard to learn what happened.