I just brought home a nuc on the 23rd of May. I noticed a frenzy of activity last week-- and they have been hostile. I have had wet sheet on for a few days and husband made a quick screened robber entrance last night. Unfortunately it didn't fit tightly at the bottom on one side, which we didn't see right away. Lots of activity again today and I saw the little suckers sneaking in the tiny gap. I taped it up. There is still a lot of activity and lots of bees on the inside of the screen as well as many hanging on the outside. Also lots of buzzing. I am wondering what I am dealing with inside the hive, but don't know when to check it. Do you go out in the dark and try to assess the damage? I'm not even sure if there is a nuc left to keep fighting for. VERY frustrated!!! This is only my second hive, so we are still newbies. Would appreciate any help.