We considered this, but ultimately we felt that a series plot doesn’t necessarily work on the scene level, which is why you would link the plot grid.
For series, we recommend you create a series plot grid that is not linked and plot out the major arc and plot points of the series. Then in your book grids which are linked, you can incorporate those major series points into each book’s grid by either copying it word for word or perhaps by adding additional information within the context of that book. This way you can look at the overarching plot for the entire series separate from each book.
Click on Plot and click the button to create a General Plot Grid to have one that isn’t linked to a book.
Let me use an example. Say you had a pirate epic series, Pirates of the Mediterranean. You create a series plot grid that is not linked to any book. The series grid might have a plot line for the main overarching story—like the Book Scenes plot line in your book grids—without needing to cover every scene in the story like your book grid does. This Main Plot might have cards like Sails to Sicily to Find Treasure and Wins epic battle but loses Bill Turntable, setting up for next book. Both of these plot points may take up several scenes in the actual books themselves, but for your series plot, you don’t need to cover all that detail. In addition to your Main Plot you might have a Love Plot which covers the drama-filled love triangle between love interest Rebecca Goose, Bill Turntable, and Captain John Cardinal. You can cover the general twists and turns in that series grid, and let each book cover the finer points in their grids.
I hope this helps.
As far as plot points that disappear, that sounds like a bug needing fixing. I am sure they still exist in your project but perhaps have no “parent” anymore and are orphaned. I can restore them if you need them. I will have to add that to a list of things to check. It probably isn’t something that happens often, moving scenes between books.