In Fukushima Prefecture, the site of a nuclear accident in 2011, so much radioactive material fell in a wooded area that it has become a radioactive forest. NHK has visited the area several times since the accident to see how the radiation is affecting its flora and fauna. Using state-of-the-art technology to survey the forest, scientists have found severe contamination in flowers and nuts, and even irregularities in the chromosomes of animals. We examine how the contamination is circulating inside the forest.