The brand new series of Grand Designs is as enthralling and ambitious as ever. It opens with a gravity defying three story tree house in Gloucestershire - built by two nature lovers determined to live life high up in the branches. To follow there's a giant house of fun near Horsham, complete with secret doorways and hidden passages. There are twin 21st century farm buildings in Devon and a unique home on the edge of the Lancashire moors inspired by drystone walls. Hidden away in an Essex woodland there's a sleek black bunker-like home designed for an artist, and in rural Pembrokeshire a hand crafted recycled house built for less than thirty thousand pounds. And that's not forgetting the astonishing Cornish home made with beautiful flowing steam bent ash. Kevin McCloud is on hand to witness all the twists and turns experienced by those willing to put everything on the line to build their once in a lifetime homes.