Mary becomes shocked when she comes back to Scotland in "Reign" season 3 episode 16.

"Reign" season 3 episode 16 is entitled "Clan." According to Spoilers Guide, Mary becomes stunned by the new Scotland, which is described as "treacherous." As per the publication, this leaves her with no choice but to hide her real identity as a royal, since she has yet to know whom she can trust. As the series runs, it is assumed that Mary will meet someone she views as trustworthy.

Episode 16 is also set to see Lola try to help Mary when Elizabeth made an attempt to introduce her to an insufferable suitor. Because of the former's action, which planted a seed of doubt in her, Mary started to question Lola's purpose. Along with Mary, who tries to get acquainted with her new surroundings, the episode is also set to see Charles secretly plan to renounce Catherine's powers. Whether Mary's doubt on Lola goes away is yet to be revealed.

Previously, Mary opted to leave France in "Reign" season 3 episode 15, according to Spoilers Guide. Entitled "Safe Passage," Mary knew from Lola that she had the opportunity to go to Scotland unharmed; however, she had to do things fast and quiet. The episode also saw Catherine set up for murder, which made Mary think twice because she considered saving Catherine. However, Mary decided not to stay, as doing so would compromise her route to Scotland, as per the publication.

"Reign" season 3 episode 15, "Safe Passage," aired on May 23, while episode 16, "Clan," is set to air on June 6.