This is the LVS & Co Formal - My Dark Valentine that is being released on Valentines Day. It's a 10 piece set, with multi options. The first black gown with the princess gown prims that Ravenlynn released. I love the floofy wrists & collar. It remmys me of a feather boa, which we all knows tote means "class". :)
The LVS & Co sim (Cassiopeia Island) is having a Valentines Event (Valentine's on the Square) where the vendors of Cassi-Square, and LVS will be setting out Valentine gifts for everyone to come by and pick, (they will not be hidden). More details on Ravenlynn's blog post: Valentine's on the Square (Feb 14-Feb17th)
This gown will be released to purchase on Valentines Day - after 7 copies will be randomly given out to customers who are roaming around the sim, picking up Valentines and doing shopping throughout the day (from noon to around 6ish slt).