Short and quiet, "Fallen angel" is about finding someone in a place where light seems impossible. The speaker says "Here we are," as if announcing arrival, and then pictures two people as lamps in the dark. The image of a "lightless starlight" is a nice contradiction: a star is supposed to shine, yet this one is dark, waiting for something to switch it on.
The line "And yet somehow we found each other" is the emotional center. The word "somehow" suggests surprise, even luck, as though the meeting was unlikely. The speaker seems relieved and tender rather than loud or dramatic. By the end, being together is what lights the star "tonight," so connection becomes the source of brightness.
The mood is hopeful, intimate and a little fragile. Since the title is "Fallen angel," the speaker may be someone who has lost their own glow, and finding another person lets them shine again. That is an inference from the title and imagery, but it fits the poem's gentle sense of rescue.