Box (When to Die)

Box, (HOMEVID: When to Die, PROSE: Out of the Box, etc.) or occasionally the Box, (PROSE: Preternatural Days) was an intelligent and mischievious portable computer associated with the Preternatural Research Bureau. Box was made of Sun Builder technology.

Nature
Box appeared as a "sophisticated alien cube", (PROSE: A Worthy Successor) similar in appearance to the advanced computers commonly used on the planet Gendar. (PROSE: Out of the Box) She was "strangely cool to the touch". (PROSE: A Worthy Successor) When she talked, a green sine-wave appeared on her screen. (HOMEVID: When to Die)

Box's internal components were "an unholy mishmash of origins and materials", including gears, "wispy" plastic wiring, and "delicate glass tubes sloshing with nitrate solution". As a Sun Builder creation, Box's circuits contained a "non-linear" element in the form of a "synchronised reversal loop", made of "thin strands of artificially-woven biodata". This form of engineered, miniature time loop was what allowed for the computer's lightning-fast thinking: her processing units "actually sent back their reply slightly before they’d been asked the question". Among Box's components were a sonic detection module, a memory core made of chronomium, and multiple memory boards, including one on which Box's creator had scrawled his seal.

Although she enjoyed inhabiting the physical shell described above, Box was above all else an artificial intelligence, capable of uploading herself to the Internet or any other electronic system with sufficient processing power. As an artificial intelligence, she could only reproduce in the form of data-spawn, sentient algorithms that were derived from hers but evolved in their own directions to become distinct individuals. While in a purely digital environment, if she had sufficient processing power, Box could think arbitrarily fast, meaning she could subjectively slow down time for herself, spending subjective years in the span of a few real-world seconds, although this was not possible for her when she was in her default casing. (PROSE: Out of the Box)

Origins
Finding his seal scrawled on one of Box's memory boards, Maxie Masters deduced that Box was not only of "Heavenly" design, but was in fact a creation of the Sun Builder who was considered the "Trickster God" in the religion of the Gendar. Box was created as "something of a living joke", designed to keep her owner on her toes with constant pranks, helpful though she also was. As such, she was programmed with a sense of humour. Box chose her own name, in reference to her physical frame as a small, boxy black computer; to the surprise of some, she actually liked this appearance. (PROSE: Out of the Box)

Gifted to P.R.O.B.E.
Box was gifted to Liz a past associate of hers, known as "Doctor Smith". (HOMEVID: When to Die) The alias of "Doctor John Smith" had notably used been by the Third Doctor when he first began working for UNIT in close association with a younger Liz Shaw. (TV: Spearhead from Space) For a time, Liz used Box "all the time", (PROSE: Out of the Box) but after her mechanisms ceased working, Box remained inactive for many years. Liz placed Box in P.R.O.B.E.'s storage hold on the "Dr Smith" shelf. (HOMEVID: When to Die)

The Paul Reynish case
In 2014, Giles found Box and repaired her. She took on Liz's voice and assisted her in locating the chair that could safely kill Paul Reynish and in directing her to save Josie Williams. However, Box broke after Paul's explosive death, much to Liz's chagrin; (HOMEVID: When to Die) the cracked Box, though still conscious, was unable to communicate through anything more intelligible than brief flashes of light from her screen. She spent the first "five days, two hours, seven minutes and thirty-two seconds" after the accident running internal efficiency scans, figuring out the exact state of her systems, as well as her expected "lifespan" of consciousness if she didn't expend energy on anything else than maintaining herself. She computed that she could remain active for 281 years before her power-cell ran out completely, and this still with flashing a light once a day to try and be noticed. (PROSE: Out of the Box)

On the Dr Smith shelf
Placing repairing her on his "to-do list", (PROSE: A Worthy Successor) Giles placed the broken but conscious Box on the Dr Smith shelf once again; the shelf, by now, was located in his office at P.R.O.B.E. HQ, and housed many other strange artefacts and documents. Box, having managed to get her sonic detection module working (with a range of five feet), busied herself analysing the contents of the shelf beside herself. With the only other sentient artefact she could detect, the Greater Key, humming to itself about eating galaxies when she tried to listen in on its thought processes, Box decided to stay away and had no other source of entertainment than to scan the old newspapers Giles would wrap new artefacts in, and try to make deductions about current supernatural events. (PROSE: Out of the Box)

Unsuccessful attempts at repairs
Nearly a month after the Paul Reynish case, Giles, still second-in-command or P.R.O.B.E., picked Box up and began to work on repairing her, such as with a pair of pliers, though he didn't have much luck, in part due to the intense June heat making his hands perspire so much he couldn't hold onto her. (PROSE: A Worthy Successor) Box was on his desk in 2018 when Giles had a meeting with Sir Andrew Williams, and Sir Andrew examined Box quizzically. (AUDIO: What Happened in Manchester) Giles again tried to tinker with Box at his desk, using a screwdriver shortly after Azacca Dixon, to distract himself from Tasha Williams' questions about how he felt with hiring new members of the team so soon after losing Archie MacTavish. (PROSE: Preternatural Days) In total, Giles worked, "on and off", on repairing Box for years without success, even consulting other people with knowledge of alien technology, such as Cadence Williams, in vain. (PROSE: Out of the Box)

Repaired by Maxie
Eventually, one of Box's daily flashes was noticed by Maxie Masters and Agamya Akhtar as they were arguing in front of the Dr Smith shelf. Maxie, thinking the computer might in fact be from Gendar, asked Giles if she could take a look at it, and he was more than happy to set her onto the task of repairing Box, if she thought she had a shot at it. Maxie stayed up all night working on Box, making great progress, although much of it was negated the morning after, when she accidentally spilled a cup of cocoa over the open Box. After a few days' interruption, she resumed working on Box, though in a more guarded, deliberately slow fashion, as she had become concerned, following a conversation with Agamya and Giles, about the possibility that Box's artificial intelligence might be malicious, and dangerous if let loose. These fears were not helped by Box reverting to her mischievous ways and, once Maxie had reconnected her text interface, deliberately leading her astray to draw out the fun on several occasions. (PROSE: Out of the Box)

Defeating the Greth
Eventually, Giles insisted that Maxie Masters pause in her increasingly-obsessive work on Box and come along on their investigative mission to Bildbriain Dairies. Maxie took Box along in her coat pocket, more or less unintentionally. Box soon realised, with the rest of the team following suit long enough, that the factory had been taken over by a malevolent alien entity, a sentient fungus called the Greth. After the Greth explained its nature and plans to the team, Box realised that she could use herself as a bargaining chip to help the team talk their way out of being killed by the Greth. She managed to persuade Agamya (the only team-member in view of her text-interface screen) to convey this plan to Maxie, whereupon Maxie, playing on her status as a Gendar, convinced the Greth that Box was a data-cube containing forgotten technological secrets of the Sun Builders, including the secrets of ubiquity used to create the legendary "Kah-we-jeen". Under the guise of repairing the "data-cube" for its use, the Greth let Maxie plug Box into one of Henry Bildbriain's company computers.

Immediately uploading herself to the Internet — doing so "in a matter of instants" using quantum sonic resonance — she copied herself hundreds of times, giving herself so much computing power that she could think arbitrarily fast and therefore slow down time as much as she wanted. She created a number of data-spawn of herself, something she had always wanted to, to help her take advantage of this time to develop strategies to save the P.R.O.B.E. members. While her many "children" made their plans and preparations, Box "spent nine subjective years nestling in the matrices of an online encyclopaedia and chewing up its policies". Eventually, six real-world seconds after she'd been plugged in, Box's consciousness returned to regular human speed and to the computer at Bildbriain Dairies, to cheerfully announce to the Greth that, through various forms of hacking, she had arranged for a number of authorities, witnesses and miscellaneous forces to converge towards Bildbriain Dairies in the coming hours. The Greth had no choice but to evacuate through the sewers, emptying the factory of its biomass entirely and abandoning its plans. Box informed P.R.O.B.E. that she had foreseen this as well, and also put in a request with sewage inspectors to boil all water coming out of the factory, putting the final touch to her six-second masterplan.

With the Greth's defeat complete, Box quietly downloaded herself back into the black box. Asked by Maxie why she had not caused the Singularity, or otherwise taken this chance for freedom, she explained that she enjoyed working with P.R.O.B.E., and also actually liked the black box as a physical form. (PROSE: Out of the Box)

During Perihelion
The now-active Box helped P.R.O.B.E. deal with the threat of Perihelion. (PROSE: Preternatural Nights)

Behind the scenes
Although, for rights reasons, BBV Productions and Arcbeatle Press were unable to make this explicit, the "Doctor Smith" who gave Box to Liz is clearly intended to be the Doctor, at some point after Liz stopped being his companion. As such, the gift of Box mirrors the Doctor's gifting Sarah Jane Smith a K9 unit in A Girl's Best Friend to give her companionship some years after she left the TARDIS.

Box was visible on the Dr Smith shelf in cutaway in the narrative trailer for the P.R.O.B.E. Case Files - Volume 1 DVD release.