Sarah Niles

One hundred years ago, the Universe’s greatest library was sealed off with only a cryptic warning as explanation: "Count the shadows." It now appears that the shadows are on the move again. The Doctor and Donna work to uncover the Library’s secret.

Sharon faces the reality of having a giant new roommate in the form of Rob, the man whose child she happens to be carrying. As Rob tries to fit himself into his new London life, he connects with an old school pal, Dave, who's evolved into a delightful scumbag, and meets Sharon's feral brother Fergal - all while trying to cook up a proposal to help Sharon feel better about their situation.

Rob and Sharon split up to celebrate their bachelor and bachelorette nights, both of which spiral out of control. When the big day arrives, Sharon's maid-of-honor is missing. With the pressure mounting and her stomach nearly bursting, Rob and Sharon must figure out a way to get through the big day - not to mention their wedding night - despite a major eruption.

The couple invite friends and family to a very awkward celebratory party. The animosity between Sharon and Rob's mother boils over, and they make a very unfortunate discovery about another family member.

As Sharon and Rob try to plan a wedding together, Rob suddenly faces an uncertain financial future. When Sharon calls Rob's mom to invite her to their wedding, her future mother-in-law reveals that Rob has withheld a secret from his past.