The present study attempted to determine differences between children and adults in the resolution of third-party property disputes involving different claims for ownership. Children (n = 110; mean age ± SD = 6.3 ± 1.2) and adults (n = 74; 37.5 ± 12.6) watched videos depicting ownership conflicts between two characters who held opposing claims over an object and were asked to decide who should own it. In the stories, each character based her claim on one of four distinct arguments: Discovery, Creation, Occupation, and Transaction. A key difference between these claims lies in the presence or absence of a "first possession" element: Discovery and Creation imply prior possession of the discovered or created object, whereas Occupation and Transaction necessarily involve a preexisting owner. We found that children assigned ownership to prior possessors in the stories twice as much as adults (Medians = 4 and 2, out of four cases, respectively; p < 0.001) and favored discoverers and creators substantially more than adults. Previous studies have demonstrated the importance of first possession in the adjudication of ownership for both children and adults. The present study deals with first possession as instantiated in Discovery and Creation episodes and provides novel quantitative evidence that children value first possession significantly more than adults. In contrast with previous studies, we found that discovery trumps creation in certain contexts, suggesting that narrative and contextual details influence children's reasoning.