The Mark of the Berserker: Part One

Plot:

Rani finds a pendant which can be used to control people and takes it to Sarah Jane's attic for Mr. Smith to analyse, but there is no one there and she leaves it. Clyde's estranged father Paul comes to see him, though he has never been much good to his son. Clyde takes him to Sarah Jane's house to prove to his father his accounts of his adventures, but Paul sees and pockets the pendant. When Rani's father challenges him and explains its powers Paul forces him to do press-ups in the street and tells Clyde to forget his mother and his friends in favour of his father.