A method of constructing an article of footwear having a molded integrated vamp and sole is described. The method comprises molding the integrated vamp and sole with an external cavity formed in an exterior surface of a heel portion of the integrated vamp and sole. A plug is formed for close fit in the cavity. The plug has inner and outer surfaces and a contour side wall. In one embodiment of assembly, a heat reactive glue is applied to a bottom surface of the cavity and the inner surface of the plug, and at least a portion of the heel portion, having the cavity, and the plug are heated whereby to soften the glue to effect a bond between the bottom surface of the cavity and the inner surface of the plug when the plug is placed in the cavity with the inner surface of the plug facing the bottom surface of the cavity. Pressure is applied across the heel portion and the plug to bond the plug in the cavity. In another embodiment of assembly, the plug is glued in the cavity during assembly by applying a glue which is not heat reactive.