|Country of origin||United Kingdom|
|Original channel||BBC 1 (CBBC)|
|No. of episodes||6|
|Other Seasons||Series 1, 2, 3|
Mrs Croker teams up with a Victorian scientist, Mr Darcy. They develop an elaborate plan together to catch masses of ghosts. Mrs Croker wants to use the ghost-energy so that she can become immortal. Returning to the modern era, 25 years have now passed since Roddy and Tessa last defeated Croker, and Roddy is a doctor with two children who are called Leo and Bex. Roddy is nervous when they question him about his old stories of the Ghost Hunter and William. William meets Roddy again, but Roddy can no longer see him, due to the loss of his second sight.
Using the time portal, Croker and Darcy make millions of pounds, and plan to buy Roddy's former school,and set up "THE GHOST SCHOOL", which is now derelict and abandoned, apart from the ghosts who reside there. The year in the future is 2027. Bex and Leo, having gone through the time portal to 1890, help a Victorian baby (Albert Povey) who is seriously ill, by bringing him back to 2027. Their father, Dr Roddy, gives the baby antibiotics which saves its life, but by doing so, changes the course of history. Albert grows up to be a successful doctor and in the future, is widely celebrated. Meanwhile, an angry DeSniff thwarts Croker's plans by withdrawing all of the money Croker and Darcy have saved. A final showdown between the pair sees DeSniff donating all of the money to the charity which has been set up and is celebrating Albert Povey Day.
Bex and Leo, back in Victorian times, where they have returned the baby Albert to its parents, get back to the Time Portal, only to find it is closed. William and his friends risk sacrificing themselves in order to re-open the portal. Bex and Leo return to the future and in doing so, the time portal closes, perhaps forever.
Arriving at the place where the derelict school and The Ghost School had once stood, they see it is now a new hospital, dedicated to Albert Povey. Roddy comes out and tells them they are just in time to see a new ward opening up in honour of the man who donated so much to help... the DeSniff Ward. Back in Victorian times, two of the ghosts have emerged unscathed from the time machine, but William is nowhere to be seen. Roddy is seen in his office, where William makes his final goodbyes to him. Roddy is delighted he had the chance to see his friend one last time.
- Time And Time Again
- The Time Travellers
- A Matter Of Life And Death
- Hunter At The Door
- Trapped In Time