At some point in Gwen's questline, she will suddenly vanish from the ship. This has left players scratching their heads, attempting to figure out where she could have gone and why. Finding her is required to complete her questline, so determining where she is is integral to progress.
Where Did Gwen Go?
Taking Time Off
After visiting Gwen's childhood home Villa Maggiore, she will feel unwell and ask for a few days of privacy in the Taking Time Off quest. Unfortunately, even her favorite recipe black coffee won't shake her out of her stupor. Once the three days are up, if you visit Gwen's cabin, she will not be there. If you look around the ship, you will find she has disappeared completely and left the ship for a new location.
Asking Other Spirits
Asking around about Gwen will give you insights into her whereabouts. Simply talk to the other spirits aboard the ship, and they will give you details that will help you to determine Gwen's location, eventually leading you back to Villa Maggiore. Sail there and talk to her, but be warned: this will trigger the final quest in Gwen's story, which means things are about to get very real and very emotional!