When the USA legal drama Suits returned for its eighth season, it didn’t take long to address the elephant in the room. Or rather the elephants not in the room.

“Harvey, I’m only going to ask you this once,” Donna Paulsen (Sarah Rafferty) tells her boss, Harvey Specter (Gabriel Macht), in the season premiere. “Is there a chance that you are overreacting to Mike having just left?”

“I don’t know, Donna,” he says, before adding, with typical swagger and lack of self-awareness: “But to tell you the truth, I don’t care.”

Fans know better and, more important, so does Suits. In its new season, the show doesn’t pretend the departures of the leading actors Patrick J. Adams, who played Mike Ross, and the new royal Meghan Markle, who played Mike’s love-interest-turned-wife, Rachel Zane, didn’t leave a hole in the show.

Instead, it will explore how losing Mike affects the remaining characters, particularly Harvey, while also using the change as an opportunity for a reset. The recurring characters Alex Williams (Dule Hill) and Katrina Bennett (Amanda Schull) are now series regulars and a new enterprising, disruptive lawyer named Samantha Wheeler, played by Katherine Heigl, takes the firm by storm.

Aaron Korsh, the show’s creator, said, “I’m going to miss Meghan and Patrick, but I think there are still interesting stories to tell. And then on the other side of it, you have a rejuvenation with new energy, on screen and off.”

With shows like House of Cards and Transparent losing lead actors because of sexual misconduct allegations and Roseanne because of racist tweets, there is no shortage of TV shows reinventing themselves on the fly. (Roseanne is technically becoming a new series, The Connors.) But the exit of Mike, a secretly unqualified attorney who has been the show’s moral centre, is more akin to planned TV departures of the past, like Wayne Rogers’ Trapper John McIntyre from M.A.S.H. or George Clooney’s Doug Ross from ER.

“About a year ago, Patrick called me and let me know he wanted to move on,” Korsh said. “So we had that amount of time to figure it out.”

With Mike and Rachel married and gone to Seattle to start a socially conscious firm, the show will continue to focus on the story of Harvey, the hardworking, take-no-prisoners, romantically-challenged head of the re-christened law firm Zane Specter Litt. For Macht, the new twists, turns and personnel represent an energy infusion for the long-running show, which remains USA Network’s most watched programme.

“There’s going to be enough of the old that fans of the show love,” he said. “But also new dynamics which challenge the status quo.”

The most notable new dynamic involves the arrival of Heigl’s Samantha, a protege of Robert Zane (Wendell Pierce). Viewers first meet her not in a courtroom or a corporate office, but as a ruthless aggressor in a kickboxing ring, a sign that for all her beauty and brilliance, she is foremost an aggressive, formidable player as Robert and Harvey engage in power struggles at the firm.

Heigl has long been a fan of both Suits and Korsh, she said, praising in particular the showrunner’s knack for creating “strong female characters.”

“They know who they are and are at ease in their own skin and don’t take [expletive],” Heigl said. “When they apologise, they mean it. I don’t know how many times a day I apologise when I don’t have anything to apologise for.”

The actress, who found fame on the medical soap Grey’s Anatomy and was most recently seen along with Hill on legal drama Doubt, adapted quickly to the brisk banter of Suits, her new co-stars said.

“Katy brings incredible charisma, humour, groundedness and stability, and she gets the syntax and rhythm of the show immediately,” Macht said.

“That new energy makes it a reboot,” he added. “Also the infighting at the law firm — how we can love to hate each other, how we can each win to become the insider we all are striving to be.”

But while the firm’s attorneys are marked by their outsiderness in the elite world of corporate law — whether because of hypernerdiness (Louis Litt, played by Rick Hoffman), class (Harvey), gender (Samantha), or race (Alex and Zane) — the show distinguishes itself with its relentless yet mostly unremarked upon commitment to diversity and inclusion.

“For me, they’re just human beings who happen to be various genders and races,” Korsh said. And yet he recognised that such people are also shaped by the cultural and social experiences of their lives.

“Shonda Rhimes said she tries to make the show look like the world around her — I read that and I like that thought,” he said. If during casting you “bring in everybody — not just one kind of person — and you cast the best actor for the role, you will automatically have a diverse cast.”

Such subtleness and sensitivity is appreciated by cast members like Hill. His character, Alex, is a dogged, resourceful attorney, and he hopes that people root for him because “he’s someone who dared to dream, and to see the dream come to pass has taken a lot of work.” While his African-American identity is an important dimension, it does not always drive the plot.

“In my life, I’m always aware of the fact that I’m a black man, but it’s not at the forefront of every conversation that I have,” Hill said. Though the new characters and relationships might be a jolt to longtime Suits enthusiasts, the creators promise that the show’s aesthetic sensibility — defined by quick-paced dialogue, edgy workplace fashion and contentious rivalries, inside and outside the firm — remains intact. And while they emphasise their enthusiasm over the new direction and possibilities, in quieter moments they allow that the transition has been challenging at times.

“That first week back was really heavy,” Macht said wistfully, in a decidedly un-Harvey mode. “Patrick and I started out together on this show, we made a deal to challenge and support each other and create an atmosphere of a set family. So when he left, it was a massive void for me, personally, thinking my partner is not here.” That said, “there’s enough excitement and continuing of similar themes and new themes that people will be engaged,” he added. “Hopefully one day when this thing ends, he’ll come back and do an episode.”