Plumbing and heating expert Richard Trethewey makes a House call to repair an old steam radiator that squeals and leaks. With the help of the homeowners (and their Great Dane), he replaces the air vent and repairs the shutoff valve. Back in the loft, Richard, general contractor Tom Silva, landscape contractor Roger Cook, and host Kevin O'Connor try to guess "What is it?" Then Roger helps a homeowner prepare his raised garden beds for a long, cold winter.