That '70s Episode

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 “That '70s Episode” – When the past becomes the key
In this episode, the three sisters used a special magic to go back in time, returning to the 70s – the time when they were still children, and their mother was still alive. The purpose was to destroy a demon that Patty had defeated, but survived thanks to a magical loophole. However, the most important thing was not only defeating the demon, but also the opportunity to meet their mother – who they lost when they were very young.

 Patty Halliwell – The Brave Mother
Finola Hughes portrayed Patty as not only a powerful witch but also a loving mother, willing to do everything to protect her children – even when she did not know clearly who they would become in the future. Patty's eyes when she first realized that the girls were her children from the future... really touched the hearts of viewers.

One of the most memorable lines:

""I don't understand how this is possible... but I feel it's true. You're my daughters."" 

And the final moment when the girls have to return to the present, leaving Patty behind – all three of them hugging their mother in tears – is one of the most heartbreaking farewell scenes of the series."