1x15 - Tegami Bachi: Letter Bee

Lag and Niche are riding a carriage on the way back from a delivery, and the two other passengers are a passionate couple named Bonny and Moss. They've promised to marry each other, but Frank and his gang, who's proposal was rejected, are chasing after them. Niche, after hearing that eloping means getting to be together with the one you love, drives away Frank so Bonny and Moss can be happy together, but the real reason Frank was chasing them turns out to be something else...