This report presents results from the "CPB-PBS Ready To Learn PEG+CAT" Content Study. "PEG+CAT" is a unique transmedia property that emphasizes early mathematics and problem solving. Each episode is structured around a specific mathematical problem the characters are trying to solve together. It includes video episodes, interstitial video, online games, and a tablet-based app, that allows children and their families to engage with the same characters, settings, and narratives on multiple devices, across various physical and social settings. The study examined how a sample of 59 four-year-old children engaged with and learned from selected sets of "PEG+CAT" videos and interactive games over five less-than-hour-long interactions. These five independent, unmediated interactions took place in a controlled learning laboratory setting. This study is one of an interrelated series of studies included in the Ready To Learn summative evaluation, being conducted by EDC's Center for Children and Technology and SRI Education's Center for Technology in Learning (EDC/SRI). EDC/SRI are serving as the external summative evaluators on behalf of the Ready To Learn partnership among the US Department of Education, the Corporation for Public Broadcasting, and PBS. [For the executive summary, see ED599706.]