Jon Yoo closed a seed round for Suger, his YC Winter 2023 marketplace startup, and then his co-founder walked out. What followed was five weeks with zero customers, a solo rebuild, and a run from $500K to $2M ARR in six months with a team of five. In this episode of Year One, Miles and Grant go deep on the moment Jon knew the split was coming and why neither side said it out loud sooner, the deliberate customer-sequencing strategy he used to climb from early logos like Fivetran toward Snowflake, and what YC partner data actually says about co-founder breakups as a leading killer of otherwise fundable startups. They also surface a complicating detail: Suger's Series A press materials still list two co-founders, leaving the solo-founder narrative murkier than the headline suggests. The episode closes on the structural question that outlasts the people drama: can a company scale past Series A when one person is still the single point of failure? Essential listening for any founder navigating a co-founder split or building toward their first institutional round.