Alex, a teenage dump truck who has spent his entire life working in a quarry alongside his parents, has a chance encounter with two city dwellers: another truck Nick and a street washer Julie. These new friendships open Alex’s eyes to the vast, wondrous world beyond the quarry walls. But danger looms on the horizon – a long-dormant volcano in the mountains has begun to wake, threatening everything in its path. Now, Alex and his friends must dream up a way to defeat the elements and convince the divided truck community to unite before it’s too late.