The wait is finally over for "Arrow" fans as the show is scheduled to return to the CW with an all-new episode Wednesday, Jan. 15.

As fans may recall, before the series went on a brief winter hiatus it ended when "Brother" Sebastian Blood used the Mirakuru serum to create a super-powered army, and injected Roy as his next test subject. It was also revealed that Slade Wilson is seeking revenge against Oliver and standing behind Blood, a mysterious villain who wears a skull mask. 

In the build up to the upcoming episode, titled "Blast Radius," "Arrow" star Stephen Amell revealed that his character, Oliver Green, "is obsessed with whomever the guy in the skull mask is," reports TVLine. "He's losing his mind, freaking out because Mirakuru has a tie to the past for him," he added.

"As we're learning, all the stuff that happened on the island and [on the freighter] was not good," Amell recalls. "It was stuff that he thought he had buried in the past. So for it to crop back up again is not a good sign."

Although viewers are aware of Oliver's past odyssey and Arrow's present-day crisis, Amell says, "Oliver has no idea" that Slade is in Starling City.

In addition, Oliver's personal life will take a turn for the worse when his ex-girlfriend Laurel makes a return and hits rock bottom due to drug and alcohol abuse.

"Oliver's going to play a part in [that arc], but not in the way you might think," Amell teased. "Oliver has always been very protective of Laurel, and her moment of clarity, so to speak, happens after an encounter with Oliver unlike one that we've ever seen on the show."

TV Guide provided further insight about Katie Cassidy's character, Laurel, unveiling that her spiral into substance abuse will worsen after she discovers a dark secret. However, on the bright side, executive producer Marc Guggenheim says that "Laurel will be learning that her sister is alive."

For fans wondering what's going on with Alex Kingston's role as Dinah Lance, executive producer Andrew Kreisberg reveals that viewers can absolutely expect her to return to the show.

"We're such huge fans of Alex and she's quite the busy this year - she's performing Macbeth with Kenneth Branagh - so we were so glad that she was available for a few episodes to come back, because we have some great stuff with the Lance family," he said to TVLine.

Kreisberg continued, hinting about what to expect later on in Episode 14.

"Everyone in the Lance family has big secrets and it's all going to get blown wide open - but in a good way."

Watch a preview below.