Constance Marie Constance Marie

For Switched at Birth's Regina Vasquez, readjusting to life after rehab will prove to be more than difficult.

"When Regina comes back, there's an adjustment period," Katie LeClerc tells "We're used to not being a cohesive family, but it's especially hard on [everyone]."

Returning summer shows: Where we left off

Adjustment is a major theme for all the characters this season after the winter finale left many of them at a crossroads: Regina (Constance Marie) accepted that she had relapsed into alcoholism; Lana (Annie Ilonzeh) ran off with Angelo's (Gilles Marini) baby;  John (D.W. Moffett) won the Senate election; Bay (Vanessa Marano) and Daphne (LeClerc) argued over a guy — again — and Toby (Lucas Grabeel) announced his engagement to Nikki (Cassi Thompson). When the series picks up Monday (8/7c, ABC Family), Regina will come home to find that life in the Kennesh and Vasquez household had moved on without her.

Check out what to expect from Regina's recovery, an impending wedding, old and new love interests, and more from the cast and creator below.

Regina has a tough road ahead
Staying sober is difficult enough, but when Regina's welcome home isn't so welcomed, she'll face a tougher reality than she imagined. "Daphne really took that opportunity with Regina being in rehab to get close to the Kennish's and spend lost time with them," LeClerc says. Adds Lea Thompson: "It's really hard for Regina to adjust because she's fragile and we think we know everything."

Check out 24 (not-so) guilty-pleasure shows

A new Vasquez family
With Regina feeling like an outsider, she decides to stay with Angelo. And soon someone else is knocking on their door. "You get to see what the Sorrento family would've been like," LeClerc says. But Bay joining the household doesn't necessarily sit well with Daphne. "It's actually Daphne's turn to be jealous of Bay being with Regina," Marie says. "She gets to see what it's like for someone to come into your house and take over your mother for a little while."

Poolside fun and bikinis galore!
Since the season takes place in the summer for the first time, "we're excited for a fun change with bikinis, no more uniforms, no more school — just 10 episodes of what the Kennish and Vasquez Sorrento family does in the summer months," creator Lizzy Weiss says. "Gilles is topless!" Marie adds.

A health scare
Could John's new job be too much pressure? "For John ... there's a stress level introduced that has ramifications on what happens in Episodes 4 and 5," Moffett says, hinting at a heart attack. "Let's just say John doesn't deal with the stress very well." As for Kathryn, Thompson says she's frustrated now that she's back to being a housewife after the excitement of publishing of her memoir.

Add new fall shows to your Watchlist

An It's a Wonderful Life episode
Get ready for a "what if?" scenario, which will show viewers what life would've been like had Regina revealed that she had known about the switch early on. "The episode [shows] how it would have radically changed our universe," Marie says. In addition to seeing Bay, Daphne and Toby as babies, we'll also see major physical changes for Bay, a personality change for Daphne and a relationship change for John and Kathryn. Jokes Thompson, "I'm the expert having done Back to the Future, where I played a million aspects of the same person, so they had to come to me [for advice]."

A possible wedding
"Toby and Nikki are still engaged and in these next 10 episodes planning the wedding is a huge [arc] for my character," Grabeel  says. "But the question of the marriage actually happening is up in the air." John and Kathryn, though, hope it doesn't happen. "As a parent, John never thought the marriage was a good idea and he's praying he comes to his senses."

Bay and Daphne are at odds again
The girls are on the outs yet again when the season picks up. "The struggle with Daphne and Bay is that they want to be close and then the jealousy sets in. Their relationship gets pretty rocky," Marano says. "But then they find a way to bond towards the end over boys again. [Bay's ex] Ty (Blair Redford) is back and Daphne gets a fabulous new love interest who is British."

Watch a clip from the premiere:

Additional reporting by Natalie Abrams