Greg and Helen Watson have bought a home in one of the most expensive areas of Sheffield, South Yorkshire, but it's too cramped for their needs and needs renovating. What's more, their third child is due in 18 weeks and they are desperate to move in before then. Architects Howard Evans and Prue Chiles are given the job, but with the Covid-19 lockdown, the wettest month on record and some major design differences, the build is in danger of collapsing before their £120,000 budget runs out.