Kristen found out that John and Marlena still had deep feelings for each other. After she read his letter that he wrote before his "execution". She schemed to keep John and Marlena away from each other. But Marlena found out about everything and wanted to expose her. Eventually Kristen convinced Marlena to keep silent until the birth of her child. In Paris, Kristen lost her child in an explosion, in which her mother and Stefano were killed. Stefano turned out to be alive and helped Kristen who didn't want that John and Marlena found out that she lost the child. She wore a pillow under her clothes. Then they would end up together again. Stefano still in love with Marlena provided Kristen a pregnant look-a-like called Susan. She would take her place at doctor's appointments, etc… This plan worked very well, until Laura saw her pillow slip away… Jennifer finally found out how evil Peter was and wanted to divorce him. Peter couldn't live with this and wanted to kidnap Jennifer, with Stefan (thetvdb.com)