Viewers can enter a magical world after the “Pretty Little Liars” Season 6B premiere Tuesday. Based on Cassandra Clare’s “The Mortal Instruments” book series, “Shadowhunters” will introduce Clary (Katherine McNamara) as a young girl who discovers that she is part angel, making her a shadowhunter. The shadowhunters fight demons and other evil beings, and Clary will have to join them if she wants to save her mother from a terrible villain. Here is what viewers should know before tuning into the new drama on ABC Family (soon to be Freeform):

1. True To The Books

During the Television Critics Association press tour, executive producer Ed Decter explained that the writers have followed the books. “We stay unbelievably true to the spirit of the books, and we love the books,” Decter said (via Variety). “We wanted to have surprises both for the real hardcore fans and then we also want to introduce the viewers who have never been introduced to the world carefully and slowly so that they can get caught up in it like we are.” The source material includes not only Clare’s original “The Mortal Instruments” series but also spinoffs such as “The Bane Chronicles.”

2. Romances

Two words: relationship drama. Expect the young characters of “Shadowhunters” to have a lot of feelings for each other, along with a few forbidden romances. Clary will also have a love triangle with her best friend Simon (Alberto Rosende) and shadowhunter Jace (Dominic Sherwood). “[Simon] knows her better than she knows herself and is there for her and knows how to comfort her and how to help her more than anyone else,” McNamara told Spinoff Online. “But Jace understands her new world and understands everything that she needs to learn and know. Jace is there to challenge Clary and help her grow and help her realize things in herself that she never thought possible. We really play up that struggle.”

3. A Few Changes

Although the show stays “true to the spirit” of Clare’s book series, expect some specifics to change. Clary has been aged up to an 18-year-old about to enter college. “We are doing our own thing, but we are definitely pulling as many elements from the book as we can,” McNamara said.

Watch the “Shadowhunters” trailer below:

4. Racier Content

With the network changing names from ABC Family to Freeform, “Shadowhunters” will be a little more risque than the fare the network has offered in the past. “I said [to ABC Family/Freeform] the show was going to be darker, sexier,” Decter explained (via TheWrap). “It’s got some racy content, and they said, ‘Bring it.’”

5. A Look Back

While Clary has had a mundane, typical upbringing, the people she is meeting haven’t. The show will give viewers a look at some characters’ backstories. While immortal warlocks like Magnus Bane (Harry Shum Jr.) won’t be able to fit their whole histories into a TV show, teenage shadowhunters, such as Clary’s love interest Jace, will have their pasts exposed.

“Everyone’s backstory is covered, without giving too much away about the show,” Sherwood told KSiteTV. “Jace’s backstory — we’re actually in episode 9, and we’re starting to look at it now, in episode 8 and episode 9 ... I think it’s very important to know where all of these characters came from, and how they became who they are, so the audience and we know a full version of these characters. Why they are who they are. Why they behave the way they behave, and so on, and so forth.”

“Shadowhunters” Season 1 premieres on ABC Family/Freeform Tuesday at 9 p.m. EST.