1) Hanna Marin betrays Spencer Hastings by having an affair with Spencer's Husband Toby Cavanaugh, both Hanna and Toby gaslight Spencer into losing her sanity so that Spencer gets institutionalized, Hanna divorces her husband Caleb Rivers and Toby divorces Spencer, both Hanna and Toby get married, and Hanna legally adopts Spencer's kids and is now their only mother.
2) Mona Vanderwaal betrays Spencer Hastings by having an affair with Spencer's Husband Toby Cavanaugh, both Mona and Toby gaslight Spencer into losing her sanity so that Spencer gets institutionalized, Toby divorces Spencer, both Mona and Toby get married, and Mona legally adopts Spencer's kids and is now their only mother.
