Netflix's hit TV series Heartstopper has just entered its third season. The cast is all around excellent, but what holds it together are the heartbreaking performances of its two leads.

Can one write a love letter to a love letter?

I can try.

Because Heartstopper, the candy-colored (but never cloying) teen television show, full of animated butterflies, first loves, and effervescent pop tunes, feels like a love letter to younger selves everywhere – the younger selves we were, or wish we'd been, or, perhaps for many viewers, still are.

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No matter which category you fall into, Heartstopper can help you marvel at the wonder and friction and exuberance and possibility of that age, and serve as an important reminder that love can be every inch as dramatic as pain or trauma. If that's not a love letter, I don't know what is.

Now launching its third eight-episode season on Netflix, Heartstopper was created and written by Alice Oseman based on her webcomic-turned-book series of the same name, which she started writing when she was just a teenager herself.

For two seasons, Heartstopper followed the budding romance of British teens Nick Nelson (Kit Connor) and Charlie Spring (Joe Locke) as they meet at Truham Grammar School, become friends, and fall for one another.

All, of course, while surrounded by an ebullient, motley friend group: high-achiever Tara; her goofy girlfriend Darcy, who's coping with a tough home life; film-obsessed Tao; budding artist Elle; bubbly, insecure Imogen; moody musician Sahar; and Isaac, always buried in a book.

In Season 3, though the group chat is still everything, the kids on it are moving on to I Love You's, to sex and university decisions, some of the first real, stressful choices anyone can make. (This season does up the physicality, but everything remains very TV-14.)

While the cast is all around excellent, what holds it together are the heartbreaking performances of its two leads: Connor layers Nick, heretofore an athletic, golden retriever type, with trepidation and insecurity, and Locke plumbs Charlie's mental health struggles with gentleness and grace.

(This show has, understandably, skyrocketed their careers: Locke also stars in the new Disney+ show Agatha All Along, and Connor is currently in previews for a Broadway production of Romeo & Juliet in which he's starring opposite Rachel Zegler, an illicit clip of which has set the internet positively aflame.)

It must be said that the secondary characters are no less impressive: Nick's mom, played by Oscar-winner Olivia Colman, doesn't make an appearance in this season, but instead, we meet his Aunt Diane, played by Hayley Atwell (of Marvel and Mission: Impossible fame), as well as prolific character actor Eddie Marsan as Charlie's therapist and even a cameo from Bridgerton star Jonathan Bailey.

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To adapt her runaway hit for the screen, Oseman told The New York Times in 2023, she remained as faithful as possible to the graphic-novel original, even including two-dimensional animations that enliven the live action: snowflakes falling, leaves swirling, lighting bolts flying, and yes, butterflies.

"It's all about those little moments in a relationship where your heart is beating and your feelings are so big," Oseman said.

In Season 3, it's also about those moments when love and life get hard; from time to time, dark clouds of animated pencil lines will surround a character as some darkness creeps in.

As trite or simplistic as it sounds, Heartstopper is, at its core, about love. But love, in all its manifold, Venn-diagram-testing forms – romantic, platonic, familial – is the least simple thing there is.

These young people, at the age where you're just becoming responsible for yourself, but not yet quite sure how to be responsible for other people, are testing the limits, to see where different forms of love cohere and where they conflict.

As Charlie moves toward Nick, he moves, necessarily but unintentionally, away from his sister, Tori.

Now that Nick and Charlie are dating, as are Tao (William Gao) and Elle (Yasmin Finney) and Tara (Corinna Brown) and Darcy (Kizzy Edgell), Isaac, with no interest in coupling up, feels left behind by the friend group that was once an unshakable unit.

Written with nary a gimlet eye, and without the poison of well-intentioned, middle-aged cynicism seeping in, Heartstopper didn't make me envious of the young or glad I never have to be young again, it made me grateful I was ever young at all.

Because what a gift it is, to have been on both sides of that divide, and to grow into whatever the future may hold. To wit: When Nick is on vacation in Spain with his aunt and her family, he confesses to her that Charlie has an eating disorder and he doesn't know how to help. She, in turn, delivers one of the sly, universal but still somehow unexpected sucker punches at which Heartstopper excels.

"Standing together even when it's hard, but also knowing that sometimes, people need more support than one person can give," Aunt Diane tells Nick, her face full of worry, that turns to joy as she then gets to tell him the good news: "That's love, darling."