Blackadder Back and Forth was a feature film produced for the Millennium to and is the final story of the Blackadder series. It brings back the old Blackadder actors as well as a few new guest appearances.
The story begins with a montage of various members of the Blackadder Dynasty ranging from tapestries to old photos before properly starting on New Years Eve in 1999, where Lord Edmund Blackadder V is holding a New Years Eve feast for his friends Lady Elizabeth, the Archbishop Flavius Melchett Archdeacon Darling and Viscount George Bufton-Tufton. Blackadder reveals he has made a working time machine, built from blueprints by Leonardo da Vinci himself, and leads them down to his cellar to show it. Blackadder bets that he can go back in time and bring any item of his friend's choosing for £10,000 each, he is tasked to bring back the following:
- A Roman centurion's helmet.
- The actual wellingtons worn by the Duke of Wellington on the day he won the Battle of Waterloo.
- And a really smelly pair of 200-year-old underpants.
Blackadder assures them he will be able to do this and explains that to them a few seconds would pass so it would look like he'd stepped into the time machine and out again, and with him the items they had asked for. However once he steps inside it's revealed with Baldrick's help Blackadder is going to scam his friends out of their money by simply giving them some of his stuff and Baldrick's underpants, the time machine being fake and made by Baldrick using da Vinci's blueprints, and with a few flicks of the dials the time machine rumbles, Blackadder is content and prepares to collect his money........only to open the door and see that he and Baldrick are now in the Cretaceous Era and are soon attacked by a Tyrannosaurus rex. Baldrick saves the both of them by shoving his underpants in front of the Tyrannosaurus which causes it to fall down dead. Now one of the greatest questions in the world has been answered: It was in fact Baldrick's underpants which caused the extinction of the Dinosaurs.
To Blackadder's amazement the time machine Baldrick has made is a fully function machine, and praises Baldrick by calling him a genius, and in one fell swoop takes it back when Baldrick reveals he didn't have time to draw numbers on the dials, meaning they can't get home, with their first destination being 'two watermelons and a bunch of cherries'.
Blackadder tries fixing this by putting the dials back in the positions he thinks they were at before they set off and they land back in his now empty cellar. With nobody there, Blackadder thinks everyone got bored and went back upstairs for Christmas pudding. He goes upstairs only to be shocked at the sight of Queen Elizabeth I with Lord Melchett, with the two of them confusing this Edmund with their Edmund. Queeny demands Edmund give her a present, with her ordering his death when his attempt at giving her a gift card fails. Blackadder narrowly avoids death when he gives the Queen a mint and she absolutely loves it, and gives him her crown in return, though she does order him to find more mints in the next five minutes or she'd 'crush his skull like an egg'. As he leaves Blackadder bumps into someone and apologies as he helps pick up his things, one of which he notices is a manuscript for Macbeth, Blackadder realises he's just bumped into William Shakespeare. After asking for his autograph with his ballpoint pen Blackadder promptly punches Shakespeare in the face, in what he called revenge for 'every school boy and school girl for the next 400 years' Blackadder claiming because of his work many children would suffer in school learning about his works and calling his dialogue of 'Hey nonny nonny' crap. He then kicks Shakespeare in the shin, mainly for Kenneth Branagh's four hour version of Hamlet, with the now confused and disheartened writer naturally not knowing who Blackadder was talking about.
Asking Baldrick to remind him to kill him if they ever get back home Blackadder tries adjusting the dials again and he and Baldrick are transported to another point in time, they land in a forest and at first everything seems to be fine, but they are suddenly caught in a trap by Robin Hood (who looks and acts like various members of the Flashheart family) and his Merry Men. Like with the Queen, Robin confuses Edmund with a Blackadder from this era and is about to fill him full of arrows, but before he can Blackadder has one question for him and his Merry Men, if they steal from the rich and give everything to the poor, then why don't they just keep all the cash they take? This flawed method in Robin's ideology strikes a nerve in Robin who tells everyone to shoot at Blackadder, only for them to shoot Robin, killing him and Blackadder taking not only his hat but also has sex with Maid Marian.
Blackadder is now getting concerned; along with not being able to get back to their time they are now also changing history, first they killed the Dinosaurs and then Robin Hood, he tells Baldrick that they need to be careful. At the Battle of Waterloo the Duke of Wellington is just about to reveal his plan on how they are going to defeat Napoleon Bonaparte to the Duke of Darling, when he is crushed by the time machine, killing him instantly. While the Duke of Darling mourns the loss of the Duke of Wellington and his plan, Blackadder steps out of the time machine and steals the Duke's wellingtons.
After narrowly escaping an epic space battle Blackadder and Baldrick end up in yet another unknown time period, when Blackadder asks Baldrick what he can see he reveals people wearing skirts, leading Blackadder to think they've landed in the 60's but in fact they have landed in Roman Britain at Hadrian's Wall, Blackadder deciding to get a Roman centurion's helmet while they were there. Blackadder discovers the time machine is starting to send them back in time based on his and Baldrick's DNA as they see Centurion Blaccadicus, Legionary Baldricus and Consul Georgius being told bad news about the situation they are all in by General Melchius. Blackadder steals Georgius' helmet right before the Scottish attack the wall.
Becoming discouraged Blackadder feels they will never get back to their own time, however Baldrick comes up with 'a cunning plan' saying that when people are about to die their whole life flashes before their eyes, so if Blackadder were to drown he should see his life flashing by, so he'll remember what positions the handles of the time machine were set before they started their adventure. For the first time in history a Blackadder actually agrees that a Baldrick's plan is a good one, though he does make one minor adjustment by drowning Baldrick instead in the time machine's toilet, as his life flashes before his eyes Baldrick remembers the positions the dials were in originally and both he and Blackadder are able to go home.
Finally arriving back in 1999, Blackadder is victorious as he brings back not only the items he was asked to get but some extra ones as well such as the Queen's crown, an autograph from William Shakespeare and the hat of Robin Hood. However, he soon discovers his time travelling has caused numerous amounts of changes to the timeline:
- As he had belittled and disheartened Shakespeare he never went on to be a writer, instead he went on to be the inventor of the ballpoint pen.
- Because he got Robin Hood killed,making him die much earlier than he should have, no one has ever heard of him at all.
- And worst of all, due to the death of the Duke of Wellington, France won the Battle of Waterloo and has ruled Britain for 200 years, with garlic pudding and wearing a tutu and ballet slippers being the norm.
Horrified at this Blackadder drags Baldrick back into the time machine, screaming 'We've got to save Britain!' He does this by encouraging Shakespeare, flattering Robin Hood and not crushing the Duke of Wellington with the time machine, wishing him luck at wining the battle. Blackadder soon returns back to his regular timeline to collect his winnings from his guests, when Melchett comments on what damage an "unscrupulous" person could do with a time machine Blackadder perks up, telling his guests to go and watch the New Years festivities on the TV, telling them he'll be joining them shortly, He and Baldrick go back into the time machine one last time to put into action Blackadder's 'very, very very cunning plan'.
The four guests sit down and watch the broadcast of the Royals and the Prime Minster arriving at the Millennium Dome, and out of the limousine steps Blackadder, having used the time machine to make himself King of England. Now known as King Edmund III he helps his wife Queen Marian out of the limo while meeting up with Prime Minister Baldrick as they wave to the crowd as they enter the Dome. BBC correspondent Jennie Bond gushes about the King's 98% approval ratings, the success of Baldrick's cabinet, the close friendship between the King and the Prime Minster and the dissolution of Parliament.