Brotherhood follows twenty-somethings Dan and Toby who become surrogate parents to little brother Jamie after their mum passes away. Dan is a sarcastic joker - anxious and a little uptight. Toby is a naive sweetheart with an eye for the ladies. And Jamie hasn't said a word in six months.
Thrust into a new world of responsibility, Dan and Toby are in over their heads. Will Dan ever get the upper hand on his live wire work colleague Poppy? Will Toby get together with Jamie's gorgeous school teacher Miss Pemberton? Will the boys get meddling Auntie Debbie off their backs? One thing's for sure: the brothers only have each other to rely on since, well, that's all they've got.