BroaDWcast had this story listed at the same time as Image of the Fendahl; it is assumed they followed each other.

Intro: After years spent as popsicles, the last survivors of Earth are approaching meltdown day when they are threatened by a band of out-sized picnic pests. Oh well, nobody ever said that life was fair. Join the Doctor and Sarah now as we journey to "The Ark in Space."

Outro: With the wicked, whopper wasps dispatched, nothing blocks the Earthlings' return to begin repopulating their planet, or so they believe. They will learn differently next Sunday night at 11 when we embark on "The Sontaran Experiment." [source: ChicagoEpguides]