We describe a lecture-free problem-solving Mathematical Communication and Reasoning (MCR) course that helps students succeed in the Introduction to Advanced Mathematics course. The MCR course integrates elements from Uri Treisman's Emerging Scholars workshop model and Math Circles. In it students solve challenging problems and form a supportive cohort. Analysis of course grades of students identified for intervention in the Introduction to Advanced Mathematics course showed significant improvement. The number of non-passing grades (F through C-) decreased by more than 50%, while the number of desirable grades (B- through A) increased by more than 50%. We offer insights from our experience for readers interested in developing such a course at other institutions.