This disclosure relates to a carton in the form of a story book wherein the carton includes first and second sections hinged together opening in a book opening-like action with the first section being of a hollow construction for receiving a product therein and including inner and outer panels with a support panel assembly interconnecting the inner and outer panels, the support panel assembly having a free edge portion disposed in face-toface readily separable relation to the inner face of the outer panel along a free edge of the outer panel remote from the second section and cooperating therewith to define a locking flap anchoring slot, the formation of the anchoring slot utilizing solely the support panel assembly in conjunction with the outer panel while at the same time in no way detracting from the function of the support panel assembly.