Roots: Obviously the plot owes much to the vast body of stories featuring time travel paradoxes and the design to the 1980s. The design of the reapers was influenced by the dementors from Harry Potter. City on the Edge of Forever. One of the wedding guests mentions a pub called "The Lamb And Flag", which is the name of the pub in the sitcom Bottom.
Goofs: The TARDIS key just disappears when the Doctor opens the TARDIS shell. Also, why doesn't the Doctor notice the heat from the TARDIS key when it starts glowing?
Why does Alexander Graham Bell's first phone message get repeated on all the mobile phones? Also, the message was actually "Mr Watson, come here, I want you." rather than "Watson, come here, I need you."
Why does the Reaper change its mind about who to eat when Sarah Clark screams at it? [They don't like high pitched noises?]
The Doctor tells Rose that touching her infant self would be a paradox, when it blatantly isn't. [He's simplifying the Blinovitch Limitation Effect so Rose will understand more quickly - see Mawdryn Undead.]
A number of the cars you see in the background are either too modern for 1987, or have numberplates with the post-2001 typeface.
Late in the episode, the Reapers are able to claw bricks away from the surface of the church. If the church has become that vulnerable to them, then why can't they break the windows and go in? [Perhaps the bricks in question are younger than the rest of the building - including the windows.]
The car doesn't seem to have been dented by the crash, and Peter doesn't seem to have acquired any scratches or lost any blood as a result of being hit.
Why does the car keep following Peter? [Since I posted this, I've been reminded that Godengine strongly suggests that when somebody changes history by saving somebody's life, time itself will try to rejoin this divergent version of history with the original by "arranging" for the deaths a short time later. The Faction Paradox story This Town will never let Us go indicates that the above affect can even take the form of objects spontaneously erupting out of the quantum uncertainly of space itself.]
At the end, Jackie sees both the Doctor and Rose when Peter dies - after the bit where her memories should have been wiped. So why doesn't she recognise the Doctor when she meets him in 2005? (Rose), And she should probably recognise Rose as the girl who was with Peter when she gets near 19. [She forgot in the confusion.]
Given that Rose was 19 by March 2005, according to Aliens of London, her infant self should be at least 19 or 20 months old, whilst the baby we see is clearly a lot younger than that. [However, the apparent age of her infant self does fit better with her date of birth as given in the feature on Rose that Russell T Davies wrote in the 2005 Doctor Who Annual.] Furthermore, her eye colour seems to change an awful lot during her lifetime - she has blue eyes as a baby, greenish eyes as a young child, and brown eyes as a teenager/adult.
Dialogue Triumphs: The Doctor: 'I did it again. I picked another stupid ape.'
Rose: 'Where I come from, Jackie doesn't know how to work the timer on the video recorder.
Pete: 'I showed her that last week. Point taken.'
Pete: 'I'm your Dad, it's my job for it to be my fault.'
Memorable Moments: The Doctor returns to the TARDIS, only to find that it's just a shell. Rose has her illusions about her father destroyed as Jackie and Peter are at each other's throats. Peter makes his mind up to put history back on track by running in front of the car.
Continuity: Peter Alan Tyler, Rose's father, was born on the 15th of September 1954. He died on the 7th of November 1987. He was a bit of a Del-boy type, and it is heavily implied that he plays around behind Jackie's back. Jackie is useless with technology. Mickey is several years older than Rose [Though one of the earlier instalments on Clive's/Mickey's website claimed Mickey was 20 to Rose's 19]. Jackie's full name is Jacqueline Andrea Susette Tyler, and her maiden name is Prentice.
The Doctor can bring the TARDIS back with the glowing TARDIS key, a battery, and the sonic screwdriver. This potentially enables the Doctor to heal the wound in time.
When time is damaged, the Reapers step in to "sterilise" the wound by consuming all living beings anywhere near the cause of the damage. [Some of the novels have established that sentient beings observing history "crystallises" it, so those who see Peter alive are reinforcing the damage to the timeline. Removing them might help history to heal faster.] They can be temporarily stopped by sheltering inside old buildings, but eventually they will break through. [They probably exist outside space-time and can only break through when a paradox happens - Interference mentions exotic creatures that invade normal space when history is changed. It is possible that they destroy things by destroying them backwards in time, explaining the older is safer thing.]
It's been well-established, at least in non-televised Doctor Who, that the Time Lords not only enforce the Laws of Time, but also provide a stabilising influence upon the cosmos. With Gallifrey destroyed, the rules have changed. In The Unquiet Dead, the Doctor tells Rose that her future might not happen because history is "in flux" [and BBC Books' Eighth Doctor books tend to confirm that this would happen when Gallifrey was destroyed]. However, that was simply a throwaway comment. Father's Day provides a lot more information about how history can be changed. The following analysis is, essentially, copied (with permission and a couple of extra comments) from a post by Simon Bucher-Jones on the now-defunct Outpost Gallifrey forums. Some of it may seem illogical, but then the mechanics of time travel when it comes to changing history often do.
1) Its possible to change the past in small ways:- The past of the driver of the car has changed marginally for the better (morally) as he's faced up to his actions and stayed rather than 'hit and run' -(possibly because of his deja vu nightmarish experience of seeming to almost hit this man before?) Rose's past has changed, slightly, as the stories her mother tells her about her father's death have altered. This is, of course, not a change to the way changing history works, as there have been numerous small changes in numerous Doctor Who stories.
2) However such changes must not cause a paradox. The change in Rose's history can not invalidate her desire to go back and see her dad, because if it did she wouldn't have gone back, and he'd have died in the first location, so she would have gone back, so he wouldn't have done, so she would, etc. Whereas before she believed he died alone, now she believes he was comforted by a "mysterious, disappearing, girl" Rose is not stupid, and once having encountered a time machine it is perfectly likely that her motivation becomes the strong possibility that she is that girl.
3) Small things can have big effects, saving a single life, you know to have ended, is to save all the descendants of the person who would otherwise never have been born. While not necessarily paradoxical, such an act is at best incalculable:- when the Doctor storms off originally he's mad with Rose for changing time, but he does not at that point believe this will cause a chronoclysm. This tallies with The Unquiet Dead where he says "time can change like that". Without the Time Lords, the web of time seems to be in flux, it is not against any natural law for time to alter, but it is still immoral to alter the lives of billions to save one man, and it also still risks paradoxes.
4) Looping your own worldline, going back and having another go, is intrinsically dangerous - but not fatal if you don't interact with yourself. If you do and change your own past, the part of your time line behind you winks out and you are in effect an input from a deleted universe, at which point bad things can happen. [It has been said that it's the wrong you that winks out of existence, but let's just ignore that headache for the purposes of this analysis, as after Peter is saved, there is no reason for either version of the Doctor and Rose to be at the scene, which means that Rose didn't go back to save him, which means that he died, which means that Rose went back and saved him (etcetera). Incidentally, there are previous examples of people winking out of existence for similar reasons in Doctor Who - the most likely explanation is that the Chronovores (The Time Monster, No Future, The Quantum Archangel) ate them.]
- force out of the local space/time any transdimensional engine such as a TARDIS, and
- allow entry to transdimensional predators "Reapers".
6) Reapers are opportunists that feast on areas of damaged time. This may have, eventually, a healing effect on a large scale, by "sterilising the wound" but as with maggots eating necrotic tissue, this is no consolation if to time you are the necrotic tissue. Maggots, of course, only eat diseased tissue (in this case the Earth) and don't touch healthy flesh.
7) Time itself resists change and appears to have some drive toward healing, time wants Rose's dad dead, and killed by a specific car (suggesting that the accident had fairly strong effects on the driver, which the microchange does not annul).
8) When killed by the car under time healing conditions (7), the majority of the wound (5) heals, the Reapers (6) are expelled and their victims restored, and the microchanges (1) mend the broken worldlines (4) almost cleanly.
This seems to me to be a fairly elegant 'biological' model of time that in 45 minutes allows for:-
- flexibility to travel to the past and not worry about every little change,
- a good reason why you can't keep going back and having another go - thereby filling in for the Blinovitch Limitation Effect / Principles of Linearity.
- the possibility of other paradox related highjinks that might or might not involve Reapers.
Links: Rose first mentioned her father's death in The Unquiet Dead. Jackie and Mickey both appeared in Rose and Aliens of London / World War Three. The Doctor mentions the destruction of Gallifrey (mentioned in The End of the World.
Extras: This story has an episode of Doctor Who Confidential. Mickey's website features two pages about this episode. The first shows pictures of the Doctor and Rose at her parents' wedding, and the second is about their presence at Sarah and Stuart's wedding.
Location: London on the 7th of November 1987, and an unknown date well before that.
The Bottom Line: 'Who said you're not important? Although not without its logical flaws (and, let's face it, what story about changing your own history isn't?), Father's Day is a hugely enjoyable emotional drama. Rose, Jackie, and Peter are all perfectly portrayed, the Reapers are a strong addition to the Who mythos, and you really feel for Rose's dilemma.