Make new discoveries in this concert that features a rare duo by Mozart, a glimpse at what a Brahms fifth symphony might have been, and a daredevil serenade by Dohnányi. Mozart’s duo offers both instruments opportunities to shine in its outer movements and sing a flowing aria in the gorgeous central section. The powerful opening of Brahms's String Quintet No. 2 was derived from sketches for a fifth symphony, but it’s just one episode in an energetic work that ends in a rousing Hungarian dance.