Sailor Moon R (R meaning Romance) is itself in two pieces. The first part (Episode 1-13) features two aliens and an energy-dependent alien tree. The second part (Episode 14-43) focuses around two things: Chibiusa, a little pink-haired Usagi lookalike who literally dropped out of the sky, and a family of time-traveling enemies out to stop Chibiusa and alter the future to their end. Source: absoluteanime.com/sailor_moon