A criminal case can end a lawful immigrant's life in the United States more completely than it ends anyone else's freedom, and the moment it happens is usually the plea, not the sentence. This article explains how a criminal disposition becomes an immigration consequence: which convictions trigger removal, which merely bar relief, and why the label on the offense matters less than the statutory elements and the record of conviction. It walks through the aggravated felony category and why the name is misleading, the moral turpitude concept and its imprecision, and the controlled substance rules that turn a minor possession case into a permanent bar. It explains the categorical approach that governs the analysis, the difference between deportability and inadmissibility, and the relief that survives a conviction. Worked examples follow three defendants through pleas that changed everything and pleas that changed nothing. The article closes with what a defendant should ask counsel before any plea, and what can be done afterward.