The Woman in Cabin 10

"This was meant to be the perfect trip. The Northern ghts. A luxury press launch on a boutique cruise ship. A chance for travel journast Lo Blacklock to recover from a traumatic eak-in that has left her on the verge of collapse.
"Except things don’t go as planned.
"Woken in the night by screams, Lo rushes to her window to see a body thrown overboard from the next-door cabin. But the records show that no-one ever checked in to that cabin, and no Assengers are missing from the boat.