Try this plot points exercise, that makes use of your knowledge of characters:
- Think of a novel that you know very well.
- Write down all the main plot events (boiled down to a line each) of the novel – ie, the significant moments that have an impact on the plot. Aim for ten to fifteen of them.
- Once you have this list (and note that when you boil a plot down in this way, nakedly it will probably sound rubbish – because plot usually means nothing without character) take one of the major plot events near the middle, and radically alter it…invent something new.
- Now finish the revised plot from this point onwards, thinking about the logic of events while remaining true to character. The characters are still the same people, even though the character change they undergo after the changed event may be different from that of the original.