Prepare to re-enter the world of an author whose work never fails to be original: the thick layers of riddles and enigmas are once again mixed with a deep touch of dark, cynical humor. With characters, old and new, possessing quirks and personalities so far from each others', meeting and being forced to cooperate, one could expect no less. After all, not only is the wicked elf Elaith Craulnober not fond of young master Danilo Thann (O.K., so he explicitly hates his guts), but his racism for dwarves show and having to use both her fighting and artistic skills is not exactly a pleasing prospect for him.
One of the multiple problems with the spell befalling the bards of Waterdeep is that the caster has a rather devious mind, and the defenses she carefully laid upon the spell's secret are based on solving twisted riddles, which very few people can achieve. There is such a man available in Waterdeep, Vartain, but he is already under the service of a reputed criminal, who's of course everyone's favorite rogue, the Serpent. Why was he using Vartain's services is yet unknown, but Dan and his new friends, including a young raven-haired elf bard seen on the (excellent) cover, have to cope with him and investigate the area outside the city a bit for clues.
Meanwhile, in the City of Splendors, a new foreign and illegal organization is introduced: the Knights of the Shield, sworn enemies of the rulers of Waterdeep. A plot against Khelben and his friends, whose reputation is severely attacked by the mysterious bard's spell, is being prepared and can only be thwarted if the uneasy companions succeed in retrieving the enchanted harp that is the key to the spell.
Elfsong may seem to lack some action, but it's far from the case. Again the author shows her ability to perfectly mix a meaningful plot with the sarcastic humor that apparently became a trademark and more than enough action to keep the pace. Alas, this book isn't any longer than the predecessor Elfshadow, and Arilyn's presence is but very brief and only once, but this is far from being a distraction, especially since you'll see how she's doing on her own in Silver Shadows anyway.
Maybe I loved it because of the despicable Knights of the Shield. Or maybe because of the intriguing riddles, or the themes such as music and bardcraft. Maybe it's only because I'm biased with Elaith 'the Serpent' Craulnober and he has a major role in this one. But I think it's only because it's a wonderfully written tale that should set new standards for TSR's book department. I surmise we'll never really know.