The Crystal Heart

"Mark has big plans to further his education but is convinced by his AI assistant to join her for one day in a vividly real, and sexually themed, virtual world. However, not everything is as it seems. After Mark realizes he is reliving the same day over and over, he needs to find a way out or become trapped forever. " ― quoted from this book's product page on the Amazon.com website as of 2019-03-17.