Annually, thousands of U.S. students fail high school introductory biology. The language demands of biology are large, and science teachers are often unprepared to support students' language needs. Here, we describe a 4-week summer high school introductory biology course executed in a large West Coast city. Our aim was to help 33 students recover their biology credit. A centerpiece of the 4-week course was the embedding of metacognitive language support tools in class lectures and assessments. Of 29 regular attendees, 28 passed with a C or better. Student science learning was reliably associated with use of the language support tools.