Affair between girlfriend’s sister leads to an unexpected twist

It started out as just another visit for their mom when they realized how close both girls were becoming through social media messaging over time before meeting face-to-face again after many years apart due largely because one had moved away while others stayed put resulting eventually where they found themselves alone together unexpectedly which could potentially lead somewhere new but neither seemed ready yet considering all past history making them nervous about what might happen next ending happily or sadly? Time will tell!