While hanging out by the pool with his friends, Felix makes an amazing discovery: his yellow vintage walkman picks up sounds from 1989. Felix and his friends are fascinated by the crazy, cool, and funny noises from bygone times. But, Felix also hears something disturbing. Having recently passed away unexpectedly, Felix's own mother Marijke was onto a dark secret in 1989 when she died. While searching for the truth, Felix and his friends unearth an impending environmental scandal. They wonder if it is connected, and if they can help stop an environmental disaster before it's too late.
