Safran explained that Blair (Leighton Meester) and Dan (Penn Badgley) will have an "uneasy" relationship in the CW show's remaining episodes, while Serena (Blake Lively) is set to face a "very huge turning point" after their romance goes public.
"Dan knows just how big of a presence Chuck (Ed Westwick) has been in Blair's life," he told TV Line. "The harder she works at putting Dan at ease about that the more uneasy he feels.
"And, obviously, their relationship is hard for everybody around them because Serena was and maybe still is in love with Dan. And Chuck has his issues that he's dealing with. And whenever Chuck is dealing with issues, Blair often wants to help.
"That triangle definitely comes to the end point. But the episode revolves around Serena quite heavily. It's a very huge turning point for Serena - probably the biggest one she's had since season one... it ends with many cliffhangers. We always try to make our finales really exciting and juicy and fun. But in this one, it's like a bomb gets detonated and levels everything."
However, Safran declined to confirm whether the identity of Gossip Girl will be revealed at the end of the season.
"This storyline is something we did not tread lightly about," he hinted. "We knew if we were going to open this door we had to see it through. And we will be seeing it through."
Safran recently declared that "Chuck and Blair are never over" and said that Dan may be a mere "thorn in the side".
Gossip Girl airs Mondays at 8/7c on The CW. It airs in the UK Mondays at 8pm on ITV2.
> 'Gossip Girl' exec: 'We're not taking Blair plot lightly'
Take a look at some photos from episode 17 of Gossip Girl, 'The Princess Dowry', below: