Mac based one is Aeon Timeline, specifically designed for writers who are placing characters and events in a story it's really cool feature is you can set your own year/month/day times. I've adapted it to be a project plan in part because I can collapse and expand pieces to see more or less detail. The Story arc features adapt well to pieces of a plan or separate interlocking projects.
Download a free trial to test with.
Oogie McGuire - Mac, iPhone & Omnifocus
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Paonia, CO USA