This is season 02 of the series I am writting.
You don't really need to read season 01 if you don't feel like it, even though it's very short in case you want to take a peak.
Season 01 is called "The beginning" (/s/6679847/1/Series-The-beginning).
If the case is that you do not want to read season 01, I will write a summary for you.
SPOILER ALERT
What comes next is a summary of season 01 (fic: "Series: the beginning" 8 chapters long).
Víctor Bennett and Patty Halliwell met in 1978, the first day of school when they were six years old. They became best friends, but at the end of the year Victor parents decided to move to Detroit and they stopped seeing each other.
Nine years later (1987) the Bennetts moved back to San Francisco and Patty became Molly's -Victor's little sister- baby sitter, what reunited them.
Two years later (1989) Patty's father, Allen, died after a gas explosion and not a long time after, Victor father died too. They started dating from that moment and things were working out pretty good, until Victor's mother decided to move to Detroit again just to make them apart, not succeeding. Both kept dating with Penny's and Molly's blessing, but not with Dorothy's, Victor's mother.
After a year (1990) of being in a long distance relationship, Patty got pregnant from Victor. His mother found out and made him choose between them -Molly and herself- and Patty and her daughter. Victor chose the Halliwell, so his mother pretends he died, prohibiting Molly any kind of contact with Victor, what causes her a severe depression that expresses in bulimia.
Prue is born in the last chapter (1992), and the epilogue tells about the moment when Prue and Andy -the Trudeau's and the Halliwell's were friends since they were neighbors- met a new born Piper (1994).
This is, basically, what happened in "The beginning". From here we start season 02.