Blue Drop resembles the super-powered action series Darker than BLACK in exactly one key way: both are far better than they probably should be given the common gimmicks and story elements which lay in their foundations. An amnesiac whose lost memory conceals a dark secret? Budding lesbian love at an all-girls boarding school? Lesbian relationships involving aliens from an all-female planet? A play used as a metaphor for real-life events and relationships? Certain aspect of the plot resolution which are too spoilerish to delve into here? Been there, done that many times.
For all that its story elements may be familiar, though, Blue Drop succeeds because its story is much more about the characters than the gimmicks; in fact, the character drama predominates so much that it is easy to forget or overlook those gimmicks. Sure, there is the sci fi element about aliens scouting out the Earth, but their motivations for doing so, and exactly how the Earth could be a solution to their long-term problem, are left rather vague because that aspect of the story is merely a framing device for the rest rather than the main focus. The series does have a few action scenes, but those scenes are more dramatic punctuations than any attempt to enthrall viewers with battle footage. This is, instead, a story about the timely convergence of three wounded souls and the impact that the relationship of two of them has on helping a fourth party observer realize her potential.