The Soul Trader (1970)

Coral Chase isn't your typical assassin. She's the only one in the world with the power to steal souls from the young which she sells to elderly elites so they can extend their lives. She's cornered the market for years. But after a lifetime of servicing the sick whims of the wealthy, Coral is done. One last big hit and she's over and out, and able to retire with her 12-year-old son somewhere warm and safe. With a new target acquired at a hefty price tag, she embarks on her final 'soul tapping' mission. But there's a snag. The target is not alone...and Coral isn't the only one in the apartment with murder in mind.