Kevin McCloud follows software executive Andy Bruce and garden designer Nicki Bruce, who are planning to build a "floating" house on the River Thames, which would be the first of its kind in the UK. Their architect has come up with an ambitious, experimental design that would see the whole property magically rise up with the flood waters. However, no one knows whether it will work, and the project soon becomes bogged down in the logistical challenges of bringing to fruition such a complex structure on a small island that is only accessible by a narrow footbridge.