The bond between Cat and Vincent will be put to test in the upcoming episode of "Beauty and the Beast" season 4.

Titled "Best of Times, Worst of Times," episode 6 will see the couple as they face what could be biggest challenge in their relationship thus far. Based on the official synopsis for the episode, a new enemy who is also targeting Vincent will emerge, laying his relationship with Cat on the line.

"Vincent and Cat discover that there is another nemesis out to get Vincent, which brings the gang closer together in more ways than one. Cat and Vincent are forced on opposite sides of the law, which puts their relationship in jeopardy," says the synopsis.

In the episode, Cat and Vincent will discover that they actually have two enemies to deal with before things get out of control. Both enemies are aiming at exposing and taking down Vincent. While this new challenge will bring the rest of the squad closer than ever, it will also leave the newlyweds with no other choice but to stand on conflicting sides of the law. It remains to be seen how their differing stances will cause serious troubles in their relationship in the upcoming episode.

The promo trailer for the episode shows the couple being briefed about a former Afghan sergeant who has taken down a beast before. This troubles Vincent, as he is afraid that he may turn back to being a beast while trying to accomplish their new mission.  But while Cat assures him that it won't happen, it will become too late for her to tame the beast inside her husband.

"Beauty and the Beast" season 4, episode 6 airs on July 7, 9:00 p.m. on The CW.