The Gods Time Forgot by Kelsie Sheridan Gonzalez

Irish mythology collides with Gilded Age New York in this sweeping debut enemies-to-lovers historical romantasy, perfect for fans of Outlander and A Fate Inked in Blood.

Manhattan, 1870. Rua knows only two things: her name and that she has no memories. So when the wealthy Harrington family mistakes Rua for their missing daughter, Emma, Rua goes along with the charade, hoping for answers about who she really is. As she tries to blend into a society she doesn’t remember, she’s drawn to a firmly off-limits man: the Lord of Donore, a newcomer to Manhattan society who is somehow familiar to Rua.

Finn is new to this side of the Atlantic and knows that the best way to fit in as Lord of Donore is to make friends in high places and play by the rules of society. He knows he shouldn’t become involved with a mysterious, recently missing debutante, but he’s intrigued by Emma Harrington, and Finn has an uncanny feeling that this isn’t the first time they’ve met.
With societal pressures mounting on both sides, Rua is determined to discover the truth about the missing Harrington daughter and her own past. But when her memories begin to return, they’re of a world far stranger than New York and traced in dark magic.

As ancient secrets unfurl in Rua’s memory, Rua and Finn are forced to uncover the mystery of their past and try to save their future. In this gritty and glittering romantasy, nothing and no one is as they seem.