Abstract: A third seat for an automotive vehicle having a front seat assembly and a rear seat assembly, the latter being located intermediate the front seat assembly and the third seat assembly, the third seat assembly comprising a seat portion and an upright back support portion, the seat portion being supported by a linkage mechanism on a seat frame, the linkage mechanism providing articulation that permits the seat portion to be moved forwardly toward a second seat assembly without the necessity of tiling and inverting the seat portion about a pivotal axis whereby the seat portion forms a cargo-carrying platform, the upright back support portion being foldable in a forward direction to form a continuation of the platform, the third seat assembly including a lock on the seat portion that prevents folding movement of the upright back support portion when the third seat portion functions as a passenger seat, the lock being released automatically as the seat portion articulates toward its cargo-carrying position.