Usotsuki na Stella

Al and Milo are classmates, next-door neighbors and have known each other since childhood. Milo is straightforward and honest, while Al is always carefree and it's hard to tell what's on his mind. Strangely enough, they have spent their entire lives together. Just before the holiday season, Al invites Milo to come with him on a solo trip. Milo is a bit confused by the sudden invitation, but he has no reason to refuse and accepts it without hesitation. The destination turns out to be a place they had previously visited with their families as children. When asked about the reason for the trip, Al is constantly evasive and seems to be hiding something...

(Source: Ichijinsha, translated)

Note: Includes one extra chapter.