Roots: Computer-recycling initiatives, 'Zelda Wisdom' posters ("dogs in bee costumes")

Technobabble: Gabe suffers from analogia, a condition like dyslexia where digital (i.e. digitally-transmitted) data cannot be processed by the brain - he must resort to talking or typing, and cannot even use a door buzzer.

Dialogue Triumphs: Denise on principles :Just because we don't stick to them doesn't mean we shouldn't have any."

"When did you take charge?" "Some time ago - didn't you notice?"

"That's one of the problems with artificial intelligences - they're far too smart, just when you don't want them to be."

Continuity: Obsoletion Valley is the location of what was previously a concentrated recycling plant; the initial project fell through decades ago, and the Valley has been something of a badly-kept secret ever since. The Valley stretches around twelve "clicks" long and contains up to four billion data storage items with another sixty-thousand dumped daily - everything from whiteware chips to corporate hubs. Around eighty per cent of it is useless hardware, but the remainder often contains recoverable data. Above the Valley are massed several floating homes, the abodes of data pirates who hold private sector recycling licences which they use as a cover for data theft.

In the Thirty-second century personality surgery - the refinement or manipulation of one's own personality via digital reconfiguration - is highly popular . Full personality changes are not technically illegal, and individuals wishing to adjust their personalities to a more 'retro' version are also common. The process usually involves a backup procedure whereby the patient's personality is rendered into digital form and downloaded into a separate device, then restored once satisfactorily adjusted. In order to facilitate this as well as numerous routine and mundane activities everyone has a dataport - a physical access for digital data - fitted. Additionally some computers often retain their user's personality data backup and are disposed of unwittingly; these are of particular interest to the data pirates.

Zachary Kindell was a pioneer of personality surgery whose reputation was tarnished by a perceived lack of responsibility; he gained a personal reputation as an immoral egotist. Amidst research into isolating lucrative aggression-triggers in the human brain and under threat of prosecution, Kndell died, leaving DNA-altering software, booby-trapped research and a backup of his personality scattered around the galaxy, in the hope of later achieving a form of full resurrection

Scandroids are robots programmed to detect and physically recover data-bearing refuse. If its operator dies a Scandroid is supposed to contact headquarters and wait by the operator's body until help arrives.

Certain frequencies broadcasted in tandem can disrupt the areas of the brain used for absorbing information.

A glider is a hover platform with a wind-resistant filter (Gloria's doesn't work). There is mention of liquid data storage mediums.

An instrument to scan human brains doesn't work on the Doctor. He says that he himself has 'a good grounding' in personality changing to order, although he disapproves of it in principle.

Links: The Horror of Fang Rock (the Doctor has an antique telescope)

Location: Obsoletion Valley, the 32nd Century (a decadent age, according to the Doctor)

Future History: The previous era mentioned is the Republican Era (preceding or following the Earth Empire?). During the Thirty-second century the human race develops a means of digital exchange in organic brains (the term for this, ODT or organic digital transfer, is what tips the Doctor off about the current date.) Touch screens and voice-activated computers are redundant technology. Currency is in 'cu' (credit units?)

The Bottom Line: How 'green' was my Valley?

Worthy, but hard work in places. Robson's skill in taking the extraordinary and accentuating the banal is as reliable as ever, but someone needed to trim the last episode before the unintelligible conversing androids and grunting mutants took over.