“The Originals” often connects to “The Vampire Diaries” in brief ways that don’t really require viewers to watch the flagship show. However, the CW drama will expect viewers to know about Caroline Forbes-Salvatore’s past with Klaus Mikaelson.

In Wednesday’s Season 5 premiere, Caroline (Candice King) will be called in when Klaus (Joseph Morgan) gets a little too murderous. The rumors of “Klaus the Mad” have traveled overseas, and with his siblings unable to visit him, Caroline becomes the only option. However, viewers who haven’t watched “The Vampire Diaries” might want to know why Klaus doesn’t mind her sudden appearance.

Though they met in “TVD” Season 2 when Klaus tried to sacrifice her (did we mention their history is a bit complicated?), their relationship didn’t really start until Season 3 Klaus was building his hybrid army. After making Tyler (Michael Trevino) bite Caroline, Klaus decided to heal her. This was the first time he showed affection for her, and that was when the Klaroline ship officially set sail.

The Originals Caroline Klaus
Caroline will appear in several episodes of “The Originals” Season 5. The CW/Bob Mahoney

Various life-or-death adventures happened throughout Caroline’s high school career, and if Klaus was in a position to save her, he would. Even when he put her in danger with a bite to teach Tyler a lesson, he couldn’t actually go through with killing her. Caroline knew that Klaus’ affection for her could be used to her advantage, so she’d often keep him distracted when necessary.

Klaus had kept Caroline’s boyfriend Tyler out of town, but after graduation, he let the werewolf come home. However, he made it clear that this was not a sign of him giving up on Caroline. “He’s your first love. I intend to be your last. However long it takes,” he said.

He headed off to New Orleans until Katherine (Nina Dobrev) was on her deathbed in “Vampire Diaries” Season 5. He came back to Mystic Falls and asked Caroline for her true feelings. He even offered to give up his vendettas with Tyler and Katherine if she confessed. He promised he’d never return to Mystic Falls, and she could ignore him forever after.

Caroline admitted that she had feelings for him, and they had a steamy sex scene in the woods before the Original vampire left town for good.

That was the last Caroline and Klaus saw of each other for quite some time. In “TVD” Season 7, they briefly talked on the phone when Klaus picked up Stefan’s (Paul Wesley) phone. Despite Stefan being Caroline’s boyfriend, Klaus made sure that he survived for Caroline.

The former Miss Mystic Falls tried to reconnect with Klaus when she and her twins needed a safe place. However, he and his siblings were in coffins for five years.

After waking up, Klaus discovered Caroline had opened a school for supernatural kids. He sent her a $3 million donation in the series finale of “The Vampire Diaries” along with a sweet note.

Dearest Caroline,

I have often imagined the paths your life might take, but your chosen future is more noble than I ever fathomed. Please accept this contribution to your virtuous cause.

I do look forward to thanking you in person someday… However long it takes.

Yours, Klaus

He’ll be able to thank her in person tonight. Caroline will appear in Wednesday’s “The Originals” Season 5 premiere, but don’t expect their relationship to have the same heated love/hate drama. Caroline isn’t a teenager anymore. She’s a widowed mother of twin witches (who are Hope’s classmates), and she’s the headmistress at a school for supernatural kids. She isn’t looking for a chaotic romance.

“It’s a shift from the instant fireworks of that kind of ‘young damsel in distress/bad boy with a buried heart’ dynamic that’s is so potent when you’re young,” showrunner Julie Plec told Entertainment Weekly. “As you get older, experience tells you that that kind of stuff can be just as dangerous as any monster, and so with age and wisdom comes a settled feeling of peace and maturity. Where we’re finding Caroline, she’s there, and Klaus is constantly searching for that, so it’s a whole new dynamic for them because she can be a peer to him, she can be a support system to him and have an adult friendship and relationship with him in a way that she never could back when they were canoodling in series past.”

See Caroline and Klaus reunite in “The Originals” Season 5 premiere Wednesday at 9 p.m. EDT on The CW.