Aurora's Heart. Three of Hearts Series, #3

She always follows the rules. He wants her to break them. Rookie cop, Aurora Karlsson, is desperate to prove her worth, and is itching to get out amongst the real criminals. But her mentor police partner wants her to take things slow and learn the job without taking too many risks. She's tired of being stuck behind her desk, and so when a tourist arrives at the station, panicked and in need of her help, she's eager to jump to his aid.
Jiro Nashamori is on a cruise of a lifetime to the arctic circle. The trip is supposed to help mend his broken relationship with his father. But when his father goes missing in the frozen wilds of Sweden, he finds the police are slow to react. No one seems to believe him. Except for Aurora, who goes against orders to help him. Their search for his missing father takes them deep into the frozen wilderness, where they unexpectedly become the target of an assassin.
Aurora quickly becomes more than just a rookie when she's forced to put her life on the line to protect them both. After she rescues Jiro from a frozen lake, the lines start to blur as sizzling chemistry ignites, and two reluctant hearts become one. Together they uncover a trail of underworld corruption in this romantic thriller, which plunges them into a world of organized crime, treachery, and murder.