Are the boys at the party in any danger?

The boys do not at first appear to be in any danger. The aliens do not seem aggressive and are clearly on Earth as tourists or to do some kind of research. If they had any intent to harm the boys, they would have done so. However, that does not mean that they are not dangerous. The first girl belongs to a being called Wain who is obviously very powerful and interested in other worlds. This could be for harmless reasons, or could suggest something quite sinister. Wain's Wain says she is considered Wain's property and so not permitted to do anything that might damage herself. If Enn accidentally hurts her or touches her in a way that Wain would not like, then he might be in danger from a powerful super being. The second girl seems harmless because she is a tourist, but she does not seem to like Earth much or have any sympathy for its inhabitants. Both she and Wain's Wain are completely unpredictable, and the reader and the boys can have no idea what kind of strength or powers they might possess. The third girl, Triolet, is the most dangerous. She could make Enn forget who he is if she infects him with the poem, and he will then infect others until there is nothing left of humanity. Vic saves him from this fate, but only just. Vic himself runs away scared and angry from the party, clearly having seen something disturbing when he was with Stella. Enn notes that Stella looks like how a universe would look if it were angry. This certainly suggests that she could be very powerful and dangerous.