In February 2012, firefighter Colin Gibbons and his wife Clare had their world fall apart when their eldest son Christopher was diagnosed with Duchenne muscular dystrophy, the most common and one of the most severe forms of the condition. They have a lovely house but it must be adapted to meet Christopher's needs, both now and in the future. Nick Knowles and the DIY SOS boys are reunited with designer Julia Kendall to make a two-storey extension with the help of the local community.