Brothers Simon and Peter Sweet both rival THRUSH leaders vying for promotion, do not realize that the toy hula doll they possess has an extremely powerful new U.N.C.L.E. explosive inside that is activated by heat. As the outside temperature rises, Illya and Solo try to recover it with the help of Wendy Thyme. Solo poses as a representative of THRUSH Central, but Mama Sweet a real member of THRUSH Central appears on the scene.