The One Day Ending Explains the ‘Sly and Unseen’ Meaning Behind July 15

A literary quote is the key to unlocking the Netflix romance’s secret. Spoilers.

Dexter and Emma in Netflix's One Day episode 14
Photo: Ludovic Robert/Netflix

Warning: contains finale spoilers for Netflix’s One Day.

A year before One Day author David Nicholls published the novel that made his name, his adaptation of Thomas Hardy’s 19th century novel Tess of the D’Urbervilles aired on BBC One. Years later, Nicholls described Tess to The Guardian as the book that changed his life:

“It was the first book I adapted for the screen and gave me the confidence to write something other than comedy. Adaptation does that sometimes – gives you a hand-up into new territory. Also Chapter 15 contains the germ of the idea for One Day, for which I will always be grateful.”

That germ of an idea was a quote from Tess, which is included among One Day’s many epigraphs, and it also finds its way into the final episode of Nicole Taylor’s new 14-episode Netflix adaptation starring Ambika Mod and Leo Woodall. 

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The story follows Emma (Mod) and Dexter (Woodall) elliptically over almost two decades, dropping in on them once a year on the same date: July 15 or St Swithin’s Day. That’s the first day they spend together as students in 1988, which, for most of the story, seems to explain the date’s significance and the reason the novel keeps returning to it.

However, it’s not until the book’s Tess of the D’Urbervilles epigraph – read aloud in the Netflix adaptation’s finale – that the actual significance of July 15 is revealed. In a rule-breaking flashback to a different date, Em reads the quote to Dex in December 1988. She’s bought him Tess for Christmas, predicting that he’ll never read it, but wanting to share this one idea that blew her mind as a teenager:

“[Tess] philosophically noted dates as they came past in the revolution of the year. Her own birthday, and every other day individualized by incidents in which she had taken some share. She suddenly thought, one afternoon, that there was another date, of greater importance than all those; that of her own death; a day which lay sly and unseen among all the other days of the year, giving no sign or sound when she annually passed over it; but not the less surely there. When was it?”

Tess here is considering the date of her death – a dark mirror of her birthday that she lives through each year without knowing the significance it will one day take. 

One Day finale spoilers below

In the final section of the book and the penultimate episode of the TV adaptation, Emma is killed when she’s knocked off her bicycle in a traffic accident. Not long after she and Dexter have finally found each other, they lose each other. It’s the cruel twist for which the novel became famous, but it’s more than just that. It’s also the point at which the story’s entire shape is explained. July 15 is the “sly and unseen” day of Emma’s death, “giving no sign or sound when she annually passed over it; but not the less surely there.”

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Every time we check in with Emma and Dexter on July 15, we’re meeting them on that day not because it’s the anniversary of the day they first spent together in 1988, but because years later, it will be Emma’s death day. The story is entirely structured around Thomas Hardy’s idea in Tess that each of us has this “other date” haunting our yearly calendar, which we – like Emma – will never realise the significance of, no matter how many times we live through it. Happy Valentine’s!

One Day is out now on Netflix.