Sydney Barrow is a very smart young girl who befriended Lily Tucker-Pritchett in "The Cold".
Mitchell was delighted that Lily had found someone special like her, someone who assumed an intellectual challenge, not an ordinary child. Or at least it seemed at first, until he discoverd that Sydney was much better than his daughter. After doing many activities and seeing how Sydney beat Lily in everything, Mitchell finally called her a know-it-all, which made Sydney cry. Mitchell tried to apologize by telling her to forget what he said, but Sydney said that she couldn't forget it because she had a photographic memory.
Lily was upset with Mitchell, and in the middle of the discussion, he accidentally spilled a drink on Sydney's picture and also got his watch caught in her hair by mistake, which made her to cry more. When Sydney's mother arrived, she got mad at Mitchell for calling Sydney a know-it-all and left. Mitchell then turned into Lily and asked her if Sydney was really a year younger than her.