Fire rescuers had to fetch two teenage boys Tuesday morning, who spent Monday night on Koolau ridge after realizing they couldn't finish their hike.  The two were hiking from Manoa Falls to Waahila Ridge on the other side of Manoa Valley. They called for help at 6 p.m. Monday. Fire Captain Terry Seelig says firefighters hiked Tuesday morning to the boys at about 9 a.m. and escorted them to the fire department's helicopter, where they were flown to Manoa District Park.  The boys were not injured.