It's the first of the semi-finals, and tonight the eight best cooks come together to battle in a team challenge, the relay invention test. Split into two teams of four, both groups must create one dish between them, using the humble chicken, as well as a range of vegetables, herbs and spices. Each team member has just 20 minutes to make their contribution to the dish, and they must do so without communicating with one another. It's vital the team leaves clues for each other, as each cook needs to decipher what the dish is supposed to be through the hints left behind. The first team member is responsible for designing and starting to cook the dish, with the second and third cooks contributing towards the main body of the dish and the fourth finishing and presenting it. Will the contestants be able to produce a dish that impresses John and Gregg within the time limit set? It's the semi-finals and the judges' expectations are sky high, as these amateurs battle to prove they've got what it takes to be crowned MasterChef Champion 2015.