Science fiction can handle the topic of grief in any number of ways, but it takes a particular mindset to create a lonely universe trying to make friends with people by recreating their recently deceased and sorely missed partners.

That the universe in question does this and then discovers an affinity with being a frog is an even more singular concept, even for Doctor Who.

And before all that, we have the dark spectacle of flesh-eating moths, Graham’s ever-present packed lunch, and a backwards world that is not only through the looking glass but through another looking glass on the other side. Beat that. Lewis Carroll!

Here are a few things to keep an eye out for, the next time you watch:

1. First, and most importantly, let’s talk about what Graham’s “cheese and pickle sarnie” is. This delightful flat foodstuff is a staple of British packed lunches and picnics. It’s a sliced bread sandwich most commonly filled with cheddar cheese and Branston pickle. Now, pickle doesn’t mean the kind of pickled gherkins you’d get in a burger, as it does in America, but refers to a type of chutney, brought over to the UK from India during the days of the Raj.

As for Graham calling a sandwich a sarnie, that’s equally common across both the north and south of England. The term is thought to be a simple distortion of the first syllable of sandwich, given a cute –ie suffix for affective warmth.

2. Originally, the story was also to feature a very tall white monster in a cloak, with a head like a mole and long fingers. Sadly, the character was cut for time, but he was played by Paul Sturgess — also known as "Tall Paul".

At 7'8" tall, Paul is currently the tallest basketball player in the world and the UK's tallest man. The previous record holder was Neil Fingleton, who also appeared in Doctor Who as the huge alien warlord in “The Fisher King."

3. This story is not the only TV confection featuring a talking frog that Sharon D. Clarke (who plays Grace) has been involved in. She also provides the voice of Treetog the Tree Spirit, the leader of Treetopolis, in the children's TV show Tree Fu Tom.

4. Although there have been characters with visual impairments in the past — including Ada Gillyflower in "The Crimson Horror," Mickey's Gran in "Rise of the Cybermen" and the Doctor in "Oxygen" — this is the first Doctor Who story ever to feature a blind actor, namely Eleanor Wallwark.

5. Mind you, it’s interesting that this breakthrough in disability representation sits alongside the following exchange between the Doctor and Yasmin:

Yaz: “For all we know, he took Erik. And now you want us to follow that nutter into the dark?”

Doctor: “No, I want you to follow this nutter into the dark.”

In the 15^th century, a "nutter" was simply the name for a person who gathered nuts and a "nuttery" was where they were stored. During the early 20^th century "nuttery" gained popularity as a slang term for a hospital for people with mental disorders, and their inmates were "nutters", or "nutcases" (and more recently, "nutjobs"). It’s not a kind term, but its sting has been blunted by years of use as a largely affectionate term, at about the same meaning and severity of insult as "weirdo".

6. Given how often they make appearances, you may be asking if there’s a token British comedian in the lineup for this week’s show, and thankfully the answer is yes. Kevin Eldon (who plays Ribbons of the Seven Stomachs) is a veteran of 90s British comedy TV, having appeared in everything from The IT Crowd to Knowing Me, Knowing You with Alan Partridge, as well as minor roles in Game of Thrones and his own sketch show, It’s Kevin. And as befits such a busy fellow, this isn’t the first time he’s appeared in the Whoniverse. He played Antimony, companion to the Seventh Doctor, in the 2000 animated adventure “Death Comes to Time.”

7. It’s quite a surprise that the Doctor didn’t head off in the direction of the alpaca farm gift shop (with the very low Tripadvisor rating), given how much the Tenth Doctor claimed to enjoy a gift shop. Three times he paused to note how much he loves them, once for each of his three companions. He said it to Rose in “New Earth,” to Martha in “Smith and Jones” and to Donna in “Silence in the Library.”

8. There’s a really satisfying reference to a previous Doctor Who story in this episode. Graham finds sweet wrappers outside the house, and that’s proof that someone may be inside. It’s a concept that is not unfamiliar to the Doctor, as her twelfth incarnation said the following during “The Eaters of Light,” when trying to find signs of human life in ancient Britain: “They must have left some kind of mark on the landscape. Burning huts, slaughtered locals, sweetie wrappers.”

9. Let’s talk about mirrors. As well as the portal into the court of King Louis XV that the Tenth Doctor broke through on his horse (“The Girl in the Fireplace”), there are three other separate mirror gateways to other realms across Doctor Who media; one in the Eighth Doctor comic “The Silvering;” one in the Tenth Doctor comic adventure “Mirror Image” and another in the New Adventures Tenth Doctor novel “Martha in the Mirror”. That’s if you don’t count the fact that the Tenth Doctor trapped Sister-of-Mine inside every mirror, at the end of “Human Nature” / “Family of Blood.”

10. There is, of course, an element of regional pride to the fact that Yaz mentions her cousin's love of the band Arctic Monkeys. They are proud sons of Sheffield, the city Doctor Who has been loosely set in since the Thirteenth Doctor first crashed through the train carriage in "The Woman Who Fell to Earth," and the city in which Chris Chibnall went to university.

Other Sheffield artists Yaz could have mentioned include Def Leppard, Pulp, The Human League, ABC, Bring Me the Horizon or (and this is quite unlikely given the ages of the two girls in conversation), Joe Cocker.

Do you have a favorite moment or easter egg from "It Takes You Away"?