The Reckoning - Alma Katsu

With Dr. Luke Findley by her side, Lanore McIlvrae imprisoned her immortal enemy and has embarked on a new life; now all of London is clamoring to see the Victoria and Albert Museum's "mystery" exhibit - Lanny's collections of lost nineteenth-century treasures, including the last precious gift given to her by Jonathan, the man who owns her heart for eternity. But the portal to her past opens once more as Adair, the Taker, crashes into the twenty-first century to hunt down Lanny and exact revenge for her heartless betrayal - the price she must pay for an endless love.