A little girl finds the Doctor sitting on a swing in a playground. They discuss that he is sad because he can't find his "friend". They share a friendly exchange before the little girl returns to her mother. The Doctor doesn't realise that the little girl is actually Clara herself, for whom he is looking. Clara's mother appears and scolds her for talking to a stranger.
Clara mentions having lost her "best pencil, her school bag, her gran and her mojo".
Depending on when in the 1990s this minisode takes place, Clara mentioning "mojo" might be a reference to the then-popular Austin Powers movie series, which briefly returned several outdated words to popular use, including "mojo."
This prequel was released along with the entire second half of Series 7 (episodes six to thirteen) on DVD and Blu Ray on the May 22, 2013, and as part of The Complete Seventh Series on September 24, 2013.