Tortuous means twisting or complicated. "James Bond drove his custom BMW 120 mph on the road that was tortuous in its twists and turns. He had to stop the evil madman's plan for world domination that was so tortuous even 007 could not understand it."
From Latin torquere "to twist," tortuous means something with twists and turns –– a path, an argument, a story. It is important not to confuse it with torturous, which means characterized by great pain. "The contemporary string quartet was tortuous in its tonal shifts, but only torturous at the point where the violinist ran her nails up and down a chalkboard."