This article dissects the first priced equity financing a startup raises after its seed round—the Series Seed or Series A—and treats it as a distinct transaction rather than a continuation of the seed. It works the dilution arithmetic in full, showing how pre-money and post-money valuation, the pre-money option pool, and the conversion of SAFEs and convertible notes stack to reshape founder ownership, with a fresh end-to-end cap-table example. It maps the standardized deal documents (the NVCA model forms and lighter Series Seed templates) and the economic and control terms a new lead demands—liquidation preferences, dividends, conversion, pro-rata and preemptive rights, ROFR and co-sale, information and registration rights, board seats, protective provisions, anti-dilution, and drag-along. It covers the securities-law compliance for the new issuance under Regulation D, the Delaware charter amendment and consent mechanics, the Section 409A revaluation, and the heightened fiduciary scrutiny that insider-led down rounds draw under Delaware's entire-fairness standard. Worked examples and cross-references make every moving part legible to founders, investors, directors, and counsel alike.