The Darkest Day by Britt Bury was kindly provided to me by Netgalley for Grand Central Publishing and is the first book in the Immortal Heat series.I recently had the opportunity to interview Britt Bury and was so thrilled by how down to earth, sweet and funny she is, she was truly wonderful and I am thankful I have been able to read and review her debut novel, The Darkest Day.Izel Campbell has always believed she is an immortal Fionn, with the magical ability of persuasion, that is until she travels to Scotland to visit her grandfather where she finds out she is in fact the very last human alive and has been mystically disguised – her scent, looks and emotions had all been concealed as a way to protect her.Kelvin Kerr, a Scottish Pookah warrior is on a mission to avenge his father who was killed at the hands of a rival clan - the Campbell’s, it is a feud which has lasted centuries and one he is eager to resolve but is surprised the last living heir is a human, a female and his destined mate.What a wonderful pair Izel and Kelvin made, the banter between them at times was hilarious as was the sensual chemistry, these two were made for one another! Kelvin came across as abrupt and infuriating and Izel somewhat naïve and emotionless initially due to her past but they meshed and complemented each other really well. I liked how Kelvin dealt with his conflicted emotions over choosing his family honor or protecting his destined mate, it was a difficult decision for him but he handled it all with dignity and determination. There were a few miscommunications between them which was inevitable due to the history between their clans but they were resolved perfectly.I enjoyed each of the secondary characters, especially Ryo a snarky witch, who was a classic; I loved her inner thoughts and Ramsey Gunn who was down to earth, funny and loveable. The emotions each of the characters portrayed were believable and written well.The world building in the The Darkest Day was highly entertaining; the plot revolving around the ongoing feud between the Pookahs (immortals with animal instincts and strengths but unable to shift) and the Fionns (immortals with a particular magical trait), Izel who is coming to understand more about her past as well as a future which shows a prophecy set by the dryads telling of her possessing realm-defying powers, and also the upcoming contention where the four realms will open up, there was a lot to take in but nothing I found to be confusing. (There is also a glossary at the back of the book which explains everything).Britt Bury’s writing is flawless and perfectly detailed, the pacing was spot on and the characters all well developed and each intriguing, I am more selective with the Paranormal Romance novels I pick-up now after reading a vast number of them but I am pleased another has been added to my series and author love. Overall, The Darkest Day has all the things I look for in a great Paranormal Romance, a likeable heroine with a sense of humor and honor, a strong alpha hero (with a super sexy accent) who makes you swoon, solid world-building, tension and great humor. Britt Bury is definitely an author to look out for, an impressive debut!