The Tertiary Phase, Quandary Phase, Quintessential Phase and Hexagonal Phase are respectively the third, fourth, fifth and sixth series of The Hitchhiker's Guide to the Galaxy radio series. Produced in 2003, 2004 and 2018 by Above the Title Productions for BBC Radio 4, they are radio adaptations of the third, fourth, fifth and sixth books in Douglas Adams' The Hitchhiker's Guide to the Galaxy series: Life, the Universe and Everything; So Long, and Thanks For All the Fish; Mostly Harmless and And Another Thing....

These radio series consisted of a total of twenty episodes, following on from the twelve episodes from the original two series (the Primary and Secondary Phases) which originally aired in 1978 and 1980.

The producers chose not to continue the ordinal sequence established by the Primary, Secondary and Tertiary phases. If they had done so, the fourth, fifth and sixth series would have been termed quaternary, quinary and senary. Humorously, they chose:

For "quaternary": "Quandary", which means "dilemma" For "quinary": "Quintessential", which today means "the most perfect example of something" (although the original meaning of quintessential was "fifth element") For "senary": "Hexagonal", which refers to hexagonal phases

The Tertiary Phase

The Hitchhiker's Guide to the Galaxy: Tertiary Phase, based on Life, the Universe and Everything, ran on BBC Radio 4 from Tuesday 21 September to 26 October 2004, with repeats on the following Thursdays. Episodes were subtitled "Fit the Thirteenth" through "Fit the Eighteenth". The third novel was adapted by Dirk Maggs, John Langdon and Bruce Hyman following instructions left by Adams.

Most of the original radio series cast returned, with the exception of three, due to their deaths: Richard Vernon (died 1997) as Slartibartfast, replaced by Richard Griffiths; Peter Jones (died 2000), replaced by his friend William Franklyn, with some brief excerpts from Jones' original narration used in disguised as the Book's speech-generation system changing as part of updates to the Guide from the publisher; David Tate (died 1996), who played a multitude of minor roles in the two original radio series including Eddie, the Heart of Gold's computer. Bill Wallis, who played the roles of Mr Prosser and Prostetnic Vogon Jeltz in the original series, was not available. Toby Longworth took the role of Jeltz in the new series. On the other hand, John Marsh, who was the original series' continuity announcer, returned to announce the credits. There was even a cameo role by Adams himself (who had died in 2001) as Agrajag, edited from his BBC audiobook recording of the novel.

The original novel was based on a treatment that Adams wrote for an unmade Doctor Who movie, Doctor Who and the Krikkitmen. The idea was re-proposed during Tom Baker's tenure in the title role, and again for a potential (but unmade) second television series of The Hitchhiker's Guide to the Galaxy.

Before the final episode was broadcast, BBC Worldwide released the Tertiary Phase on CD, including additional material. A DVD of the series was released on 2 October 2006 in the UK. This marks the first commercial release of any BBC radio programme in a 5.1 surround mix. The disc contains as extras: the full version of the Krikkit Song, a photogallery, the original online and radio trailers, the appearance of the series on Pick of the Week, and thirty minutes of behind the scenes video in five short segments.

Since the opening of the third book starts at the same place and time (prehistoric Earth) as the opening of the second radio series, the entire Secondary Phase was dismissed as one of Zaphod's "psychotic episodes" (including events that did take place in the books). Hints, however, were interspersed in the subsequent fourth and fifth series that would ultimately tie all five together. The UK edition of the novel was used for the adaptation—this becomes evident in Fit the Sixteenth, when the "Rory" award is said to be given for the Most Gratuitous Use Of The Word Fuck In A Serious Screenplay. The US edition of the same novel substituted "Belgium" for "fuck", as well as the explanation for why the former word is considered to be devastatingly rude in the rest of the galaxy, which is drawn from Fit the Tenth of the Secondary Phase. The broadcast version avoids saying "fuck" on radio by well-timed crashes and explosions—the CD version moves these so that the "fuck" is audible.

Fit the Thirteenth Broadcast on BBC Radio 4, 21 September 2004 Cast: The Book: Peter Jones and William Franklyn Arthur Dent: Simon Jones Wowbagger (and Vogon Captain, uncredited): Toby Longworth Ford Prefect: Geoffrey McGivern Trillian: Susan Sheridan Zaphod Beeblebrox: Mark Wing-Davey Marvin the Paranoid Android: Stephen Moore Eddie the Computer: Roger Gregg Zem the Mattress: Andy Taylor Announcer: John Marsh

Arthur wakes up in a cave on pre-historic Earth (thus ignoring the events of the Secondary Phase), on the day, four years after he last saw Ford Prefect, that Ford arrives back. Ford carries news that he has detected disturbances in the "space-time wash", and that they might be able to escape. The disturbance turns out to be an old sofa, which materialises in a field. They chase the sofa as it runs off, and then are transported elsewhere.

Zaphod and Trillian are on the Heart of Gold, without Marvin. Zaphod is extremely hung over, and upset that Trillian is dismissing the events of The Secondary Phase as a "psychotic episode". Trillian wishes to do something and is getting increasingly annoyed at Zaphod. After preparing a fabulous meal, and Zaphod still refusing to come out of the bathroom, she teleports away, telling the ship to "transport me the hell out of Zaphod Beeblebrox's life."

Meanwhile, Marvin is on a swamp on Sqornshellous Zeta, conversing with the native life-forms, mattresses. He is circling around and around on one leg, while his artificial (i.e. replacement) leg is stuck in the swamp.

Fit the Fourteenth Broadcast on BBC Radio 4, 28 September 2004 Cast: The Book: William Franklyn Arthur Dent: Simon Jones Ford Prefect: Geoffrey McGivern Marvin the Paranoid Android: Stephen Moore Krikkit Robots: Dominic Hawksley Slartibartfast: Richard Griffiths Zem the Mattress: Andy Taylor Walkie Talkie: Fiona Carew The Boy: Theo Maggs Wowbagger: Toby Longworth Deodat: Bruce Hyman Henry Blofeld: Himself Fred Trueman: Himself Announcer: John Marsh

Arthur and Ford arrive at Lord's Cricket Ground on the sofa that they had caught in the previous episode. They have arrived in the final Test match in the Ashes, in the middle of the field. A policeman apprehends them, and they retire to the pavilion.

Watching the match, Arthur drinks some tea and glances upon a newspaper. He notices the date on the newspaper, and realises that it was from the day before the Earth was demolished. A ball lands in Arthur's bag, and when the fielder comes to collect it, Arthur decides to keep it.

With the planet about to be demolished again, they then look for another lift from the planet. They discover a spaceship, hidden by a "Somebody Else's Problem field", hidden behind a screen.

The game finishes, with England winning the Ashes, and Slartibartfast joins Arthur and Ford. Slartibartfast explains that he has arrived because "something terrible is about to happen". He walks to the centre of the cricket pitch, and asks to be given the Ashes saying that they are "vitally important for the past, present and future safety of the Galaxy".

Another spaceship arrives. Eleven white robots, carrying bats, and wearing rocket pads on their shins (dressed like cricketers), come suddenly out, and start attacking the spectators and players with their bats, using them to hit grenade-like explosives at the humans present. They take the Ashes, say "we declare", and go back into their ship. Ford and Arthur catch a lift with Slartibartfast on his ship.

Meanwhile, Marvin is once again making conversation with a mattress. A similar ship to before arrives, and white robots get out and take Marvin's one remaining leg. After a brief while, they return and decide to take all of Marvin instead.

Fit the Fifteenth Broadcast on BBC Radio 4, 5 October 2004 Cast: The Book: William Franklyn Arthur Dent: Simon Jones Ford Prefect: Geoffrey McGivern Slartibartfast: Richard Griffiths Zaphod Beeblebrox: Mark Wing-Davey Wikkit Voice: Dominic Hawksley Agrajag: Douglas Adams Eddie the Computer: Roger Gregg Judiciary Pag: Rupert Degas Krikkit Man One (and Mancunian Correcting-Fluid Magnate, uncredited): Michael Fenton Stevens Krikkit Man Two (and Krikkit song by): Philip Pope Krikkit Man Three: Tom Maggs Henry Blofeld: Himself Fred Trueman: Himself Announcer: John Marsh

Slartibartfast shows Ford and Arthur an Informational Illusion about the Krikkit Wars and the Wikkit Gate, and that the game of cricket on Earth is a "racial memory" of the Wars. Investigating further, they discover that the Krikkitmen, a previously peaceful people, built their first spaceship in a year, after a spaceship landed on their planet. The planet and its sun had been previously obscured in a dust cloud that left the Krikkitmen unaware of the existence or even possibility of existence of stars. It is considered remarkable that they constructed a working ship in just a year. After they saw the rest of the universe existed, they decided to annihilate it.

Meanwhile, on the Heart of Gold, Zaphod Beeblebrox hears the noise of thousands of people saying "Wop". He intercepts them on the bridge, where he is told they want the "Golden Bail", the ship's Infinite Improbability Drive. They take it, shoot him, and leave.

Back on Slartibartfast's ship, Ford and Arthur watch the Krikkit War Crimes Trial, presided over by Judiciary Pag. Pag's sentence is that Krikkit will be locked in an envelope of "Slo-Time", until the universe has ended, when it will be released, thus saving the universe from attack from Krikkit, and allowing Krikkit to exist in isolation after the end of the universe. However, a Krikkit ship escaped.

Slartibartfast notes that parts of the key to the Wikkit Gate, sealing the envelope of Slo-Time, have been re-appearing. After a failed attempt to recover the Wooden Pillar (the Ashes), Slartibartfast plans to go to a party, to locate the Silver Bail. Ford disagrees with this objective but agrees with the concept of going to a party. They teleport from the ship.

Arthur does not materialise with Ford and Slartibartfast, but elsewhere, in a gloomy room, with signs such as "DO NOT BE ALARMED. BE VERY VERY FRIGHTENED, ARTHUR DENT". The episode ends on a cliff-hanger, with the previously unintroduced character of Agrajag saying "Bet you weren't expecting to see me again."

The episode includes several Guide interludes, notably the story of Lallafa the poet, and a description of Brockian Ultra-Cricket.

Fit the Sixteenth Broadcast on BBC Radio 4, 12 October 2004 Cast: The Book: William Franklyn Arthur Dent: Simon Jones Ford Prefect: Geoffrey McGivern Slartibartfast: Richard Griffiths Trillian: Susan Sheridan Thor: Dominic Hawksley Agrajag: Douglas Adams Award winner: Bob Golding Woman with the Sydney Opera House Head: Joanna Lumley Party Doorman: Paul Wickens Announcer: John Marsh

The episode begins with Arthur, who has been "diverted" by Agrajag, who claims that Arthur has killed previous incarnations of him hundreds of times. He also claims to have been the bowl of petunias that materialised into existence in Fit the Third. Eventually it transpires one of the deaths was at Stavromula Beta, where someone tried to assassinate Arthur, and he ducked, hitting Agrajag. Arthur however has never been there. Agrajag cries "I've brought you here too zarking soon", but decides to attempt to kill Arthur anyway.