Plot　planning　is　one　of　the　key　steps　in　automatic　generation　of　computer　animation,　aiming　at　converting　the　abstract　plots　of　a　story　into　a　series　of　concrete　actions.　This　paper　presents　the　architecture　of　plot　planning　model,　in　which　we　employ　an　agent-based　method　to　develop　the　abstract　plot.　In　our　agent　hierarchy,　there　are　two　kinds　of　agents:　drama　agent　and　plot　agent,　both　of　which　can　develop　the　abstract　plot　according　to　their　knowledge　and　strategies.　Furthermore,　to　avoid　the　irrationality　of　the　results,　we　address　a　validity　checking　mechanism　to　ensure　the　consistency　of　the　concrete　actions.　©　Springer-Verlag　Berlin　Heidelberg　2005.