Episode 4

After not one but two shock exits, and some new faces on board, the X-bus crosses yet another border and makes its way to a country famed for music and rolling hills. The new passengers are dumped in at the deep end as host Rob Brydon arranges for everyone to spend a night in a spooky castle. It’s a race through the rooms to gather clues and make it to the room with a view to finally see where they actually are. Another challenge high on a hill tests the passengers' memories, and the bus seems even more divided than ever, with the original players closing ranks against their new bus mates.

This competitive reality show sees everyday adventurers on a fantastical trek that turns Europe into a board game, with twists and turns around every corner. More epic challenges offer clues to those smart enough to figure them out, but players - and viewers - beware, there are also some red herrings scattered around.

While the passengers battle for £100,000, you can also place your own X at home by following the clues and heading to bbc.co.uk/destinationx.