As the competition passes the halfway point, Gary Lineker tests the mettle of the remaining celebrities in a spine-chilling individual challenge. With no one to rely on but themselves, those with the most backbone are rewarded. A mystery box returns and one team captain must decide whether to gamble for a potential advantage - but nothing is ever predictable. In the team challenge, romance is in the air - but the love is short-lived as a cruel rule change sparks tension.

Gary Lineker continues to put the celebrities through their paces as the competition intensifies. With the boxes opening in ever more weird and wonderful locations, the fear of the unknown shows no sign of easing - but there's a shift in mood as the camaraderie fades, replaced by growing mistrust. As tensions rise, two more celebrities go head to head in a demanding duel - where only one can prevail and the other is sent back in their box.

Gary Lineker hosts as the celebrities are pushed to the limits of both mind and body as they face two very different challenges. First, they step into a setting defined by power, pressure and persuasion, where reputation counts for nothing. Stripped of their public personas, they must rely on quick thinking to come out on top. Next, the team challenge delivers a brutal test of nerve as one group is confronted by a terrifying vertical descent, while the other battles the unpredictability of the open sea.

True colours emerge as the celebrities face individual and team challenges. A mystery box offers an advantage, but two face the Duel and only one can survive.

Gary Lineker puts ten celebrities to the test in a challenge competition with a twist - there are no rules and no instructions.