Billie Turf and Dolfie have to stay at boarding school during the summer holidays because their report cards are too poor. Everything goes smoothly until Kwel comes up with an invention that turns water into gasoline with a pill.
| Actor | Role |
|---|---|
| TTom JanssenBilly Turf | Billy Turf |
| JJan KruykMeester Kwel | Meester Kwel |
| RRichard VroomenDolfie | Dolfie |
| HHub ConstenJanus | Janus |
| FFrans KeulenHead of School | Head of School |
| SSimon van de EndeAli Kabaal | Ali Kabaal |
| PPascal JacobiStudent | Student |
| CClaire LeistraMina | Mina |
| HHub SchmitzGymnastics Teacher | Gymnastics Teacher |
| CCor van der LindenBlinkie | Blinkie |
| JJos van der LindenJossie (as Jos v.d. Linden) | Jossie (as Jos v.d. Linden) |
| LLily van DodewaartBertha | Bertha |