This being the finale episode of a the fourth series which I think is a fantastic array of stories, Goodbye Sarah Jane Smith needed to bigger and better than the previous stories which could have been very difficult as the quality of writing was so high.
The main theme was Sarah Jane realising that she's getting older and that she may not be physically able to continue to save the world.
Sarah Jane's development was wonderfully performed by Elisabeth Sladen who has such an amazing talent of being able to show the audience what she's feeling just through her eyes.
Her fear was so prominant that I felt scared for her as she knew that this amazing life she led doesn't make her invincible and that eal life can just barge its way in.
In terms of the tone of this story, I felt that this story had a more grown up feel to it which I loved by how Rani and Clyde have grown and how Sarah Jane acts differently with them knowing that their getting older by trusting them to be able to take a more dangerous role in the saving of the world.
Here comes Ruby White; the manipulative, vicious and spiteful alien who had been imprisoned by her own people for her hunger for life energy was too powerful.
I think Russell T Davies approach to introducing her character was cleverly written because he made her appear similiar to Sarah Jane so that her real agenda could be brought to the surface by getting Sarah Jane to trust her into giving Ruby what is essentially her whole life.
As Sarah Jane begins handing Ruby her keys to her home and the sonic lipstick I felt a pang of sadness and hope that Sarah Jane would realise what she's doing.
But here is where Ruby's true nature comes to fruition when she admits to making Sarah Jane ill by draining her life force.
In my view, this was a cruel and humiliating act to do to anyone but effectively emphasised Ruby's sheer sadistic and selfish character.
Another character development was when Clyde discovered that Sarah Jane had left and blamed her leaving on Rani after she suggested that Sarah Jane needed a holiday.
I could really see how much his Dad leaving him has affected him by his fear of people he loves leaving him without a word.
Additionally, their relationship took a turbulent tumble as Rani was taken a back by Clyde's outburst which at last showed how complex their relationship is.
Luke's surprise return was a nostalgic element that was fitting for the last story of the series but also enabled the character's to channel how they feel about Luke leaving.
Again, this enhanced how these characters have grown which I could relate to and allowed me to feel comfortable with getting older myself.
A different tone, a witty and complex script, great character developments, engaging music and a despicable villian that you couldn''t help but like.... at times.