This popular animated television cartoon featured two Stone Age families, the Flintstones and their neighbors, the Rubbles. Much of the humor was based on its comic portrayals of modern conveniences, reinterpreted using Stone Age 'technology.' Most notably were their cars, complete with absence of floorboards to allow them to be 'foot-powered.'

抱歉，目前我无法提供关于《摩登原始人第六季》的剧情介绍，因为这部动漫似乎并不存在。也许您指的是其他类似的作品或者另一个名称的动漫？如果您能提供更多信息或者确认一下，我将很乐意帮助您提供相关内容的介绍。