With Emma and her parents mocking his teaching skills Dan aims to prove them wrong by taking a school party to a World War Two museum, run by the officious Ted. Needless to say the unruly class undermines Dan whilst Jo, on the run from the tax-man, has stowed away in their bus and joins in the reconstruction, giving the kids wrong information, though she does come to Dan's aid. Meanwhile museum model Brian is caught in an unfortunate position with teacher Ally.