Coronation Street producer Iain MacLeod has warned there will be a "horrifically difficult" story coming up on the ITV soap.
Speaking to Metro, he said: "Something will happen that probably has the most far-reaching impact of any story we've done since I've been on the show, and I include both stints."
"Something horrifically difficult and challenging will happen that draws in three to four different clans on the Street and forces them to deal with the hardest thing anyone would ever had to deal with," MacLeod added.
Fans have speculated that the plot in question involves the health of youngster Ollie Battersby.
Coronation Street airs on Virgin Media One and ITV on Mondays, Wednesdays and Fridays.