Hostitel by Stephenie Meyer

In a world where parasitic aliens known as "Souls" have taken over human bodies, a young woman named Melanie Stryder fights to retain control of her mind and body after being captured and implanted with a Soul named Wanderer. As Wanderer experiences Melanie's memories and emotions, she becomes sympathetic to the human cause and forms an unlikely alliance with Melanie. Together, they embark on a journey to find Melanie's loved ones, challenging the boundaries of identity, love, and survival in a world where humanity's existence hangs by a thread.

Purchase from Bookshop.org