Resaca (Undertow / Rip Current) is an evocative solo guitar composition inspired by the hidden movement and energy of the sea. Written in a classical Spanish guitar style, the piece reflects the powerful yet subtle pull of an undertow through its flowing bass melody, expressive dynamics, and natural ebb and flow of tempo. Designed for beginner to intermediate guitarists, Resaca provides an excellent opportunity to develop fingerpicking technique, thumb independence, and essential classical guitar skills. The melody is carried in the bass line, encouraging players to develop balance between the thumb and fingers while bringing out the inner voice of the instrument. The use of open strings creates resonance and colour, while carefully shaped crescendos and diminuendos allow performers to explore a wide range of expression. Through its flowing melodic phrases, changing intensity, and expressive tempo variations — including a gentle rallentando at the conclusion — Resaca captures the feeling of an unseen current beneath the surface, offering an accessible yet rewarding addition to the classical guitar repertoire.