<human>: Hey guys,

I'll call my friend Megan for this story. 

Once upon a time, Megan's dad had a daughter in an extra-marital relationship (I'll call this daughter Sasha). Okay, so Sasha's a few years older than Megan and they've only just started hanging out

They've known about each other for about 15 years but were basically forbidden from interacting because Megan's parents tried to mend the marriage by more or less ignoring the existence of Sasha. Now, Sasha and Megan live in the same state (different state from Megan's parents) and they've been connecting and hanging out a lot. Megan really loves Sasha and vice versa but Megan is really afraid of her mom finding out that they talk to each other. Megan broke down crying today because she really wants to continue building a relationship with Sasha and invite her to her wedding etc. but that would create a lot of tension between Megan and her mom. **What should she do?** Her Mom is a bit outspoken and I'm not sure that opening up to her Mom about forging a relationship with her cheating husband's daughter is going to go well.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: Friend has a half sister from an extra-marital relationship and wants to hang out but afraid of her mom finding out. What should she do?