Furious that her late father only willed her his gloomy-looking mansion rather than his millions, Carrigan Crittenden (Moriarty) is ready to burn the place to the ground when she discovers a map to a treasure hidden in the house. But when she enters the rickety mansion to seek her claim, she is frightened away by a wicked wave of ghosts. Determined to get her hands on this hidden fortune, she hires afterlife therapist Dr. James Harvey (Pullman) to exorcise the ghosts from the mansion. Harvey and his daugh- ter Kat (Ricci) move in, and soon Kat meets Casper, the ghost of a young boy who\'s \"the friendliest ghost you know.\" But not so friendly are Casper\'s uncles--Stretch, Fatso and Stinkie--who are determined to drive all \"fleshies\" away. Ultimately, it is up to Harvey and Kat to help the ghosts cross over to the other side.中文剧情：
　　在缅因州的古旧庄园——威普斯塔夫里居住着胖子、瘦子、斯特里奇三个幽灵和他们善良的侄子—— 小精灵卡斯伯。这座庄园的继承人卡里根贪得无厌，为了消灭这几个幽灵，请来了著名的鬼魂研究家哈维博士，而哈维博士的女儿凯特却与小卡斯伯建立了极好的友谊。一次偶然的机会，他们发现了一种有生命的机器，卡里根在跟踪下也发现了这个秘密。卡里根将自己变成幽灵，想获得宝贝，但他最终失败了。最后这部卡斯伯父亲的复生机器被卡斯伯用来去拯救哈维博士。本片是一部真人与动画人物合演的电影，有很多滑稽的情节。全片特技出色，把男女小主人公之间的关系，用极为图像化的特技表现出来，很可爱。