We have investigated the experience of individuals at play to better understand how narrative is constructed by collaboration in pretend object play. Our study was conducted with dyads that would play together in two distinct play sessions, with each session being video recorded. Each dyad was shown the video in a retrospective protocol collection. We utilized Grounded Theory as a means of developing and testing hypotheses based on the recorded play session. This process is meant to reveal information about how individual player cognition and interaction develops narrative during pretend play. This paper presents initial findings related to narrative development in collaborative pretend object play with the ambition to use these and future analyses to create intelligent agents capable of pretend play. Present findings demonstrate the construction of narrative and collaborative play is crafted through the making and accepting of play-advancing offers, similar to scene-advancing offers found in improvisational acting.