It's all to play for as this week's six best comeback contestants return for the last quarter-final and the chance to push on into Knockout Week. Just one challenge awaits, so the hopefuls will need to go big or risk going home.Success won't be easy as the judges have invited renowned restaurant critic Jimi Famurewa to set the brief, which is all about fusion. The super six will need to create one dish that brings two unrelated food cultures and cuisines onto one plate in perfect harmony. Fusion is incredibly risky business, but done well, it can result in some of the most thrilling food imaginable.With limited places left in Knockout Week, the three whose fusions fail to make their mark will lose out on a place, leaving the best remaining cooks to take on next-level cooking, as the hunt for this year's MasterChef champion continues.