Odayaka Kizoku no Kyuuka no Susume.

When Lizel mysteriously finds himself in a city that bears odd similarities to his own but clearly isn't, he quickly comes to terms with the unlikely truth: this is an entirely different world. Even so, laid-back Lizel isn't the type to panic. He immediately sets out to learn more about this strange place, and to help him do so, hires a seasoned adventurer named Gil as his tour guide and protector.

Until he's able to find a way home, Lizel figures this is a perfect opportunity to explore a new way of life adventuring as part of a guild. After all, he's sure he'll go home eventually... might as well enjoy the otherworldly vacation for now!

(Source: Tokyopop)