Some of 2015's buzziest dramas stumbled when they were expected to soar. True Detective followed up a thrilling first season with a turgid retread. Game of Thrones tested viewers' patience with an uncomfortable rape scene. The Walking Dead "killed" a fan favorite character just long enough to convince people he had actually died before bringing him back to life.

Defying the trend is HBO's The Leftovers, whose second season has delivered one extraordinary episode after another. Among those who care about quality television, The Leftovers should be a weekly conversation starter and a top-tier Emmy contender. Instead, the show teeters on the precipice of cancellation, regularly drawing fewer than 700,000 same-day viewers — or less than a quarter of what True Detective attracted for its season two premiere.

Why has a show as brilliant as The Leftovers had such a hard time reaching viewers? It starts with sadness — the show's most dominant mode. With major plotlines about emotional trauma, mental illness, and sexual assault, watching The Leftovers isn't exactly a light capper to the weekend. This was particularly true in the first season, whose monochromatic grimness seems to have turned many viewers away, never to return. Even the show's creative team has admitted that the first season had its ups and downs. Episodes focused entirely on a single character's perspective let showrunner Damon Lindelof show off his gifts for the mechanics of episodic storytelling. But other first-season episodes, so loaded with metaphor that they fell into stasis, were less satisfying.

If you bailed on The Leftovers after season one, let me offer a plea: Come back. Because this season, The Leftovers has shaken off nearly everything that was holding it back from greatness last year. It's funnier, faster, more visually engaging, and less spiritually punishing. It has found ways to move beyond the melancholy core of its premise, just as its characters have. And with a partial "reboot" this season, it has carved out a comfortable middle ground between the one-and-done structure of anthology series like Fargo and the narrative consistency of ongoing shows like Game of Thrones.

When its first season premiered in June 2014, The Leftovers presented the aftermath of the Sudden Departure, a tragic day on which two percent of the world's population vanished immediately and without explanation. On a more conventional show — or even a flagrantly unconventional one like Lost, Lindelof's last TV project — this premise would kick off a seasons-long quest for answers. Where did everyone go? What determined who stayed and who went? Why now? Will it happen again? Was it the Rapture?

But The Leftovers is really only interested in these questions to the extent that they illuminate characters' inner lives. Lindelof and co-creator Tom Perrotta, on whose book the show is based, insist that those questions will never be answered, leaving the characters and the audience alike to construct meaning from an unexplainable phenomenon.

This season, most of the main characters moved to the eccentric town of Jarden, Texas — nicknamed "Miracle" because none of its inhabitants disappeared in the Sudden Departure. The season premiere unraveled Jarden's idiosyncrasies in vivid detail, from the man who sacrifices goats at the local restaurant to the dozens of yearning hopefuls waiting just outside town. The move to a new place injected The Leftovers with a new energy, looser and more unnerving.

Following the model of last season's most successful episodes, each hour now focuses on a distinct perspective — either a single character or a carefully chosen group. The season's first two episodes showed the same events from the perspectives of two different families: first Jarden natives Erika (Regina King) and John Murphy (Kevin Carroll), then town newcomers Kevin (Justin Theroux) and Nora (Carrie Coon). A particularly awe-inspiring midseason stretch followed Kevin as he grappled with hallucinatory madness and descended into an episode-length dreamscape. No one watching last season could have predicted these bold detours, and yet they feel organic to the show's newfound exploratory spirit.

Along the way, the existential despair of the first season has given way to occasional flashes of levity. During Kevin's dream, a security guard mutters "Congratulations!" upon patting down Kevin's shapely crotch. Later, the ghostly Patti Levin (Ann Dowd) delivers a heart-rending monologue... about her appearance on an episode of Jeopardy!. Even last Sunday's terrifying installment — which included a character dropping a fake grenade inside a packed school bus — found room for some morbid mirth. This mixture of solemn and silly keeps the show entertaining on the most superficial level, even as gloomy undercurrents linger.

And on a technical level, this season has been nearly impeccable. The standout performers from last season — Coon, Christopher Eccleston, Amy Brenneman as Kevin's ex-wife Laurie — continue to shine as their characters stumble forward. With Kevin's increasing self-doubt and mental instability, Theroux has found a new gear as a leading man. King and Carroll bring intensity and passion to the Murphys. The directors and cinematographers have framed and shot Jarden with alluring specificity. Even the eclectic soundtrack, particularly the perfectly chosen Iris DeMent-sung theme song "Let the Mystery Be," has been a treat.

Most importantly, this season — with its prehistoric prologue and hallucinatory stretches — has proven that The Leftovers is willing to change. The show isn't bound to a setting that isn't working or a storyline that has run its course. Pressing play on a new episode has become a weekly exercise in imagination. Future seasons could conceivably go anywhere.

If they exist, that is. With just one episode to go, the third season's fate hangs in the balance. The Leftovers has demonstrated taut suspense, fascinating character dynamics, genuinely intriguing mysteries, and visually stunning sequences in every episode of its second season. That's all a great TV show can do. It's up to viewers to take it from there.