The Seattle Chamber Music Society Summer Festival entered the final week of its Benaroya homestand (it moves to Redmond Wednesday) with a compelling combination of darkness and light, in a program of Dohnanyi, Prokofiev and Shostakovich.

The Piano Quintet by Ernst von Dohnanyi is his first published work, from his student years. It is a work of both youthful romanticism and surprising maturity, managing to be thematically light while harmonically rich and dark. The harmonic depth in the strings (Erin Keefe and Aloysia Friedmann on violins, Richard O'Neill on viola and Robert deMaine on cello) has always reminded people of Brahms, including Brahms himself. But there are moments in the first movement that also echo the famous piano concerto by Grieg. Festival veteran Anton Nel anchored the piano part with just the right combination of subtlety and forwardness.

The performance also included some surprising prominence from the viola, superbly performed by O'Neill, in the first and third movements. The finale is all sunshine and bounciness, a carefree country dance that provided a stark contrast to the music that followed.

There's plenty of variety within the works of Prokofiev, but his Sonata for Violin and Piano, Op. 80, has all the complex darkness of the war-torn 20th century. The performers ensured that this would be a highlight, with newly anointed festival director James Ehnes on violin, and Jon Kimura Parker, the Vancouver pianist who has been brilliant at this festival for many years.

The work begins with very somber piano, joined by a foreboding violin line, which hangs up trill ornaments like omens of uncertainty. While the austere dissonance never truly leaves the piece, Ehnes' light touch on the rising and falling violin arpeggios sounded like someone throwing a single thread of spider web over the moon.

The piano part stays mostly in the background, but Parker still managed to make it genius. The quiet, mystical chords that underlie the third movement are humble, almost pleading; quite a contrast to the sharper statements earlier in the work. The final movement has a kind of keyboard pointillism, with a return to vigor in the violin part that had the whole house standing.

Speaking of vigor, cellist Johannes Moser should win an award for most athletic performance on the Shostakovich Trio No. 2 for Violin, Cello and Piano. Joined by violinist Amy Schwartz Moretti and pianist Craig Sheppard, Moser began the work with its eerie cello harmonics that are so delicate and so high, they probably perked up every canine ear within a mile. It's not often that the violin part enters below the cello part, but that was true here.

The work did not remain delicate. Moser was losing horsehair from his bow through the Scherzo, throwing his entire body into the music with precisely directed passion. The angst-ridden composer was mourning a particular death in this piece, with emotions all over the map. The performance had that amazing combination of depth and accessibility that left the audience roaring its approval.