Catherine's team is falling apart and she begins doubting her reign when her mother comes to visit. She works hard to hide the realities of the court from her mother and puts on a science fair for which Russia must come up with the best invention.

Catherine and Peter are co-parenting their newborn son, Paul, with the help of Elizabeth and trying to avoid their feelings for each other. When Paul goes missing, Peter and Catherine are driven together in their quest to find him.