The singing foursome “The Plaids” meets an untimely end on their way to perform their first big concert in 1964. Due to the power of harmony, the ozone layer, and some “astro-technical stuff,” the Plaids have the opportunity to come back and perform the show that never was. Forever Plaid features four-part harmonies on such classics as “Love is a Many Splendored Thing,” “Heart and Soul,” and “Three Coins in a Fountain.”