The lead characters are ex-astronaut Jeff Tracy, founder of International Rescue, and his five adult sons, who pilot the organisation's primary vehicles: the Thunderbird machines.
In "Edge of Impact", The Hood's efforts to sabotage military test flights cause an experimental fighter to crash into a television tower, trapping a pair of technicians inside.
With an old friend of Jeff paying an unexpected visit to Tracy Island, International Rescue must covertly spring into action to save the two men before the tower collapses.
Travelling to London Airport, The Hood sabotages a test flight of Red Arrow 1 by concealing a homing device in a hangar, causing the aircraft to veer out of control and crash.
Reaching the tower, the brothers use the Booster Mortar pod vehicle (a mobile cannon) to fire two Low Altitude Escape Harnesses (similar to jet packs) through the window of the control room.
"Edge of Impact" is the only episode featuring The Hood in which his schemes do not involve trying to uncover the technical secrets of the Thunderbird machines, or otherwise targeting International Rescue.
Some of the episode's other hardware he describes as "frankly ridiculous" – noting, for example, that Tin-Tin is secretly updated on the progress of the rescue by flashing lights fitted to her diving mask.
[6] Sam Denham writes that the plot, involving experimental military aircraft and a TV tower, reflects the "burgeoning" technology of the 1960s – specifically, advancements in aerospace engineering and the decade's "growing dependence on telecommunications".
[8] Jeff alludes to these events when Casey's jet comes in to land, the unannounced nature of the visit leading him to wonder whether the colonel's plane might be carrying "more of Tin-Tin's admirers".
[2] According to Fran Pheasant-Kelly, an academic who has written about the series' depiction of gender and social class, this line of dialogue draws the audience's attention to Tin-Tin's "physical attractiveness" as a mostly peripheral female character, downplaying her ability to "contribute significantly to the narrative".