Sasami Ashworth, formerly the keyboardist for the L.A. indie rockers Cherry Glazerr, is a self-proclaimed “synth queen.” But her skills as a multi-instrumentalist are undeniable: She’s also composed film scores and backed Soko, Hand Habits, and Wild Nothing. Her upcoming solo debut record is inspired by, in her words, “Everyone I fucked and who fucked me last year.” “Callous,” its first single, translates that sentiment into a rigorous rock anthem that follows how far someone will go when trapped in a delusional relationship.

For Ashworth, “Callous” is a complicated word: It’s both the toughened skin that comes from exertion and also how a relationship can turn brittle. She has a special skill for articulating all the ways someone has made her feel small—slight alterations in vocal cadence from droll to tense, ghostly overdubbing, and shrilly distorted guitars allows new meaning to unfold with each line. A lyric like “I lost my callouses for you” is given more urgency by how Ashworth rushes through the word “lost,” as if she doesn’t want to admit it. An epic, two-minute synth solo closes the song in a cathartic release. Ashworth’s chronicle of self-sacrifice for an undeserving lover is heartbreaking, but its her refined and exuberant sound that makes “Callous” thrilling and personal.