Tonight's special double bill of the soap sees Sharon (Letitia Dean) arrive on Phil Mitchell's doorstep unexpectedly, desperate for his help after walking out of her own wedding.
As a troubled Sharon left her young son Dennis behind when she fled from her big day, she is eager for some back-up as she returns to get him.
When Sharon and Phil (Steve McFadden) arrive at the wedding venue, John is livid over the way he's been treated - and shows his nasty side as he becomes irate.
With Phil looking out for Sharon, it initially seems that nothing bad can happen. However, they're both unprepared for how far a humiliated John will go to get revenge…
EastEnders airs tonight at 8pm and 9pm on BBC One.
> Read our spoiler for tonight's first 'EastEnders' episode
> Read our spoiler for tonight's second 'EastEnders' episode
> Read more 'EastEnders' spoilers and news