A tonneau system for use with a pickup truck. The tonneau system includes a tonneau cover, a frame, and a latch. The tonneau cover has a plurality of tonneau sections, including at least a first tonneau section and a second tonneau section. A first hinge system couples the first tonneau section to the second tonneau section, enabling stacking and expanding of the first tonneau section relative to the second tonneau section. The frame has a first side rail securable to a first side of a cargo box of a pickup truck and a second side rail securable to a second side of the cargo box. The latch releaseably secures the tonneau cover to the first and second side rails. When the latch is released, the stacked tonneau sections are permitted to depend into the cargo box.