It was produced by the Grundy Organisation from Australia, in association with Revcom Television from France, Katholieke Radio Omroep (KRO) from the Netherlands, and Televisión Española (TVE) from Spain.

In contrast to Secret Valley, which was a commercial failure in the United Kingdom when screened there in 1985, Professor Poopsnagle's Steam Zeppelin was hugely successful in the UK, where it was first broadcast in 1987 on the ITV network, and proved so popular that it was also later repeated on Channel 4 in both 1990 and 1998.

Professor Poopsnagle, the holder of a vital scientific secret, has been abducted and his mysterious disappearance jeopardizes the world of science.

His young grandson, who assists him in his research, secures the help of Professor Garcia, a long-standing colleague and friend of the scientist.

Assisted by a group of children, spending their holidays in the Secret Valley Camp, Professor Garcia and the young boy build a flying bus.

But alas, there is a traitor in their midst passing information to the evil kidnappers of Professor Poopsnagle: Count Sator and his accomplice.

However, against all odds, and throughout countless and often irresistibly amusing adventures, Professor Garcia and his young group of friends finally win the day.

[1] Dr. Jose Calandre Garcia had been working on the theory of Mega- steam when he lost contact with his old friend Professor Poopsnagle.

Determined to continue the work that Poopsnagle had originally begun, Garcia traveled to Australia in a hot air balloon in search of his old friend.

Unbeknown to him, however, the wicked Count Sator had discovered his plan and sent his henchman Murk to shoot down the hot air balloon.

Murk shot down the balloon, but the old doctor survived the crash and was rescued by some young children from a holiday camp in Secret Valley.

Together they resolved to build a flying bus which was originally designed by Professor Poopsnagle to help them in their search for the minerals.

In a nearby deserted town, the children gathered all sorts of junk to help make the flying contraption.

With the help of the children, and following Poopsnagle's plan, the bus was eventually completed, and based on steam power it was able to rise into the sky and fly at will.

Dingle is urged by Sator to use a hang glider to keep an aerial reconnaissance on the Doctor and his band, whilst he and Murk return to the Castle to deal with Poopsnagle, who has somehow escaped from his cell.

When Sator returns to his comp, he berates Dingle and Matt for having lost the water, and commands them to raid the Poopmobile's camp.

The Doctor and children return to Secret Valley, victorious, and we see Sator riding the camel, followed by Murk Dingle and a remorseful Matt.

Followed by Murk in disguise, they make their way to a fishing village where two of the children are trapped in the hold of a ferry.

They find Garcia (but not Poopsnagle, as they do not realise that he is also in the dungeons), however Sator traps them in the tidal cell, where the tide will eventually drown them.

They escape the fire, and Sparks, back at Secret Valley, helps the situation by warning the nearby towns of Rivers Bend's distress.

It transpires that old Sid Chesney, a horse-trainer the children have been able to persuade to train their horse, also knows of the whereabouts of the fifth mineral, for he was the person who found the Salamander originally.

After they have the mineral safely in their possession, they are about to go to the race when they find that their bus has been sabotaged by Murk who has sawn the drive shaft through.

At the base camp, they decipher the coded message and to their amazement they discover that the last mineral is positioned underneath the Sydney Opera House.

Sator is heartily amused as he can see their every move on the vision bug, and he gloats in front of a terrified Poopsnagle.

Sator has also arranged for Matt to let Dingle and Murk into Secret Valley late one night to take the minerals and Salamanders from the safe in the barn.

At first the children and the doctor are unwilling to listen, but when they realize that they do not have a plan without Matt's help, they decide to give him a last chance.

With the aid of Peter Poopsnagle's voice simulator, and a bit of make up, Carmen poses as the mysterious Divina, and fools Sator completely.

Back at the doctor's laboratory, they are working on the Mega Steam problem when Sator contacts them on Matt's communicator.

Garcia concedes victory to Sator, but after the communication, he is successful in developing a small amount of Mega Steam.

Having dismissed Dingle, who angrily walked out of the castle after an earlier altercation with Sator and Murk, Sator is then left unprotected – and therefore unable to contact Dingle for help – as he himself meets a sticky end at Baby Julius' jaws, just as the others escape with their precious cargo (although Murk's fate is left unrevealed).