Bk 3/8: more time travel, cursed objects, a vow made without thought, classic rom tropes. The Túath Dé from Bk 1 makes an appearance as a 2nd main influence. There‘s a bit more at stake here re:the vow but you already know how it‘ll pan out. The female main has strongest reasons to return to 21st century of all the others. Plot twist hits & that‘s when you think, would they really?