A big scandal surrounded the previous episode of "Downton Abbey," and things may not be slowing down anytime soon.

Last week, viewers found out about the scandalous affair between Lady Mary Crawley (Michelle Dockery) and Tony Gillingham (Tom Cullen). The affair was also discovered by Spratt (Jeremy Swift), the trusted butler of the Dowager Countess (Maggie Smith), when he saw Tony kissing Mary on the cheek. Of course, Lady Violet was quick to defend Lady Mary by making up a story that Mary and Tony will be going together to a landowners conference. 

But in episode 4, Lady Mary will have to decide is she still wants to marry Tony. The official synopsis for the episode reads: 

"Lord Merton (Douglas Reith) delivers a bombshell to Isobel (Penelope Wilton), and Mary does likewise to Tony." 

This means that both relationships will be evaluated by the couples, and one of them will move forward while the other one will have to say goodbye. The question is, who of the two couples will experience heartbreak? 

Aside from the romantic angle in the episode, the next installment of "Downton Abbey" will also deal with the mystery of Mr. Green's (Nigel Harman) murder. The police will go on with the investigation, and they will allegedly find more evidences that could point them to Downton Abbey. This time, however, the police will not be pinning the crime on Mr. Bates (Brendan Coyle) anymore.  Does this mean that Anna (Joanne Froggatt) and Bates can have a chance for a romantic relationship? 

The video promo for the fourth episode of "Downton Abbey" season 5 also features Sarah Bunting (Daisy Lewis). She will have to face Lord Grantham (Hugh Bonneville) instead of toy with Tom Branson (Allen Leech) in the estate. 

"Downton Abbey" season 5 episode 4 airs on Jan. 25 on PBS.