The trio opens with one of Schumann's finest sonata movements. Sweeping, bold and dark, a long, articulated melody with arpeggiated flourishes establishes the key motifs that saturate the movement. There are two primary themes. The second is characteristically softer and more lyrical but complemented by a variation of the obstinate arpeggio as a counterpoint. The development features a delicious surprise: a deft, fugato episode with the tiniest shard of a subject, pointed pizzicato and a chromatic countersubject seamlessly derived from a background piano figure. The concluding bars whip the drama into a turbulent froth that evaporates in suspense, the air charged with tiny sparkles recalling the fugato with a Mendelssohnian magic.