Episode one sees 48 pairs of teams take part in auditions to select the eight teams who will take part in the competition. The final pairs range from 9-year-old friends, to a pair of adult fans of LEGO (aka AFOLs), girl cousins, mum and son, father and son, uncle and nephew, Cambridge University engineering students and 12-year-old pals. They all compete in one supersized challenge where teams are given the design brief in advance. For this week’s Planned Build, Brick Feast, the teams must create a spectacular LEGO banquet, which must include one seat and at least one supersized masterpiece for the table. The seat is judged equally on its aesthetics, scale, and its ability to take an adult’s weight which is put to the test by Melvin before the judges decide which two pairs will leave the competition. The first guest judge is multi-award winning structural engineer Roma Agrawal, best known for her work on The Shard.

Episode two’s theme is Movement and sees the teams compete in two challenges. The first is an unplanned build where they each must build a different mode of transport. The teams are given three hours to build a mode of transport but half way through they are surprised by a disruptive twist where they must swap with a different team, their final model being a unique hybrid of the two. This episode’s Planned Build is entitled All the Fun of the Fair and sees the teams create a miniature funfair and populate it with at least one spectacular moving ride and as much detail and story scenarios as possible. Guest judges mechanical engineer Dr Shini Somara and TV personality Richard Osman must decide which team hasn’t made it through.

Nature is the theme of episode three’s challenges. The five remaining teams must complete an Unplanned Build where they must create as many miniature unique and identifiable insects, birds and wild animals as possible in surprise15 minute intervals using no more than 15 bricks per creature, and the Planned Build sees comedian Bill Bailey and professional LEGO artist, Sean Kenney judge the creations made by the pairs as they populate a section of a nature walk with a rich cornucopia of plants, flowers, and characterful animals. Only three pairs will make it through to the final round.

In the final episode, the three remaining teams take part in the ultimate Pure Imagination Challenge where in the Unplanned Build, the teams are challenged to create a build that reflects the inner workings of a child’s storytelling imagination. They must each listen to a six-year old child’s story and then have three hours to bring their tales to life in little plastic bricks and inject playability into their builds. The best two teams then go head-to-head in the Final Master Build where they have two weeks to realise a master creation measuring 2 x 2 metres and using up to 500,000 bricks each. The build must incorporate a central structure and an environment utilising all the skills they have been tested on and developed throughout the competition. The build will then be revealed to the general public at The Design Museum in Kensington, London and is judged by comedian and LEGO enthusiast Dara O’Briain.