Ocean, nine, from Brentwood has had a tough time. His younger brother Sky died two years ago and he needs a place to escape to when things get too much for him. He also has a new baby sister which he's excited about but his house has become pretty noisy! Ocean loves marble runs because they're like rollercoasters and one day he'd like to be a rollercoaster designer. He wants a marble run den where he can get away from it all and work towards his dream.

Brothers Alec and William are very proud of their Scottish heritage. And it's not just their family they're proud of, they think Scotland has a really interesting history and they want to celebrate it. The problem is that Alec and William live in a remote part of Scotland and there aren't that many kids around to play with, so they want a den to play in that looks like a traditional Scottish castle.

Joe and Lauren get the help of experts to design dream dens for children. Nine-year-old Nya shares a room with her two-year-old brother who often wakes her at night and keeps her up to play with him. She really needs her own space to indulge her love of martial arts. She wants it to be a dojo on the inside so she can practice and not worry about her brother getting in the way.