GKIDS has released the first trailer for Cocoon - One Summer of Girlhood, and it looks like audiences should start preparing themselves for an emotional experience. The upcoming anime film blends beautiful animation with the brutal realities of war, telling a deeply personal story inspired by real historical events, and this is going to be one of those films that sticks with you. Based on Machiko Kyo’s wartime josei manga, Cocoon - One Summer of Girlhood is inspired by the true story of the Himeyuri students in Okinawa. If the filmmakers can capture the emotion found in Kyo's original work, this could end up being one of the year's most unforgettable anime films. Cocoon - One Summer of Girlhood opens in theaters in both English and Japanese on September 4.