Hot Shelter (ホットシェルター,Hottosherutā?) is an action stage in Sonic Adventure that is explored by Amy Rose, E-102 Gamma, and Big the Cat as their second, fifth (and last) and fourth (and last) action stage of their respective stories. It is located inside the Egg Carrier and there are three sections to it: a large (and fully stocked) aquarium, the inner mechanical workings of the ship, and a high speed transit system/delivery station.
The Aquarium is visited by Big and Amy. It is exceedingly large, and there are literally thousands of gallons of water splashing about in various tanks, all filled with many kinds of exotic fish. The purpose of this area isn't exactly well known, though one could assume that it is the result of Dr. Eggman's large appetite and clear lack of respect towards animals, meaning that he may keep these fish on board so he can dine on the most rare and exotic of creatures. Amy's time in the aquarium is brief, as she is simply passing through while running from ZERO, and has little time to stop and investigate. Big, however, spends his entire tenure in Hot Shelter here. He is still pursuing Froggy, and in keeping with the tradition of having many, many other fish around to distract himself with, Big can reach upper levels of the aquarium, allowing him to cast into the fish tanks that Amy passes by during the early parts of her stage.
This section is visited by both E-102 Gamma and Amy. This area consists of many large gears and computers that supposedly run the Egg Carrier. Both Amy and Gamma start in relatively the same place, near two sets of bathrooms. It is interesting to note that the Egg Carrier seems to be equipped with sinks and toilets on the lower level of the ship, as Dr. Eggman is presumably the only organic aboard. Ahead are several large gears (some of which can have their direction reversed by the player) and enemies. Amy (still being pursued by E-100 Alpha) explores a large area filled with many huge computer monitors and large machinery before escaping via balloon, while E-102 Gamma explores a station that serves as one of the many stops for the obviously expansive metro system of the Egg Carrier, and then boards it, and heads towards the next station, where he will find E-105 Zeta. It is interesting to note that in the area Gamma alone explores, the degree of "polish" is much higher, as the area has hardwood and floors and well cleaned, gleaming metal. It is somewhat similar to the areas one can see through the glass in certain portions of the "Sky Deck" stage.
The Transit System
This area is only explored by E-102 Gamma. This area begins with a high speed battle on the Egg Carrier's automated tram system, running down a long tunnel. Once the brake is reached, the tram stops at a delivery station. This area was most likely used during initial construction of the ship to shuttle construction materials back and forth. It is here that Gamma will find and face down his brother Zeta, who has taken on a different appearance than that of his brethren.
This level and Sky Deck prove that the Egg Carrier is much larger than it physically appears to be, because the characters only explore these extremely large sections of the ship with more areas still unexplored.
The Transit System is clearly very large, and Gamma only explores a portion of it. It is unknown if there are more stops identical to the one Gamma gets off at further down the tunnel the tram races through.
Something strange to note is the presence of the large bathroom facilities, and the fact some of the stalls are occupied by Kikis. Eggman is most likely the only human on the entire ship, so the need for a large set of these bathrooms is brought into question, as all of his labor force is robotic.
Of the eleven stages in the game, Hot Shelter is the only stage that is not playable by Sonic.