When another experiment goes disastrously wrong and the gang end up falling through the ceiling into the bathroom (where a shower-cap adorned Tabbris sits fuming at his young angel charges), the gang decide a change of leadership is required. Spit takes over and suddenly things seem to be going OK - trouble seems to be a distant memory. That is, until the gang's pet rat goes missing and the footprints in the fridge are bigger than any rat they've ever seen - or ever want to...