Taihou de Naisho no Hanashi H

Synopsis

Napping on the hillside, Nobita is woken by elderly men. Resting at home instead, Doraemon tells the legend of Netaroh (Sleeping Boy)—a man who slept three years, but awoke and solved his village's water crisis, having mentally worked out solutions during sleep. Doraemon produces the "Netaroh Pillow," which activates the brain to solve any problem while sleeping. Testing it with Nobita for Mom's lost ring: three minutes later, the pillow chimes, and awake Nobita finds the ring! Emboldened, Nobita plans to help others using the pillow...!