After his "brother" Gabriel was infected with a nanovirus and sent to kill everyone who stood in the way of Nicholas, Gabriel infected his fellow Lifelikes as well and together they seized Babel's upper levels and captured - and ultimately killed - the Monrova family. Still, Ana survived with life-threatening injuries and was rescued by Ezekiel and Silas. Ezekiel instructed Silas to take Ana away while he stood up against the other Lifelikes. As a punishment for his loyalty to the Monrovas, his siblings implanted an old coin slot inside his chest, threw him from the tower and left him to rot in the wastes.
But his love for Ana was stronger and the only thing keeping him from taking part in the attack and so Ezekiel decided to search for Ana for the next two years before he finally found her in the Tire Valley.