Cwmderi goes back to the future.
These characters include some who have since passed on to 'Upper Cwmderi' - Harri Parri, Maggie 'Post' Matthias, Llew, Gina and Glan.
Meic and Derek are also shocked to find Mrs Mac back behind the bar and father and son, Dyff and Mark Jones brawling in the corner.
Meic, who is the present landlord of the Deri Arms even finds himself face-to-face with a much younger version of himself.
The complex promo, produced by the channel's marketing department, uses the latest technology never before used by S4C.
'Technology has enabled us to bring together these popular characters from the past and present and place them all in one central location, the Deri Arms,' said Siwan Haf Roberts, the promo's producer.
'The village pub has been at the heart of the village and a popular watering-hole for 30 years.
'We had to search through hundreds of tapes to find the right clips so that the characters in the promo look as if they are talking to each other.
'The idea is to reflect the past three decades of Pobol y Cwm in a different and humorous way.'
The promo can be seen on S4C until October 17.