I need help with my story ideas. can someone help?

Okay so i am doing a Vampire Diaries FanFiction and i have a good plot and stuff i just dont know what could happen in the little bits so here's the plot.
Madison comes to Mystic Falls to stay with her cousins Elena and Jeremy, after finding her mother dead and her dad gone.John Gilbert her dad is dead, but Madison doesnt know, John came to Mystic Falls when his wife Sara died, leaving Madison to clean up. After John had saved Elena he died, Madison not knowing where her dad is または that Elena is her sister. Madison comes to realise that Mystic Falls is filled with Vampire, Werewolfs and Witches, but what everyone doesnt realise is that she is a Mermaid. Tyler and Madison start going out, but when she finds Tyler is a Werewolf and almost dies, Damon comes to save her risking his life. Damon tells Madiosn he loves her. Priscilla and Katherine come to town, Priscilla is a sea witch and in order for her to become human and for every Mermaid to step on ground with legs Madison has to die. Priscilla and Katherine are sisters.
So thats all i have so if anyone has and ideas please tell me