Abstract: A shelter apparatus comprises an open box base member having a bottom panel and a peripheral, box side wall. A front and a rear shelter walls are removeably engaged in spaced apart vertical slots on the inside of the box side wall. A tension beam is engaged with, and extends between the front and rear shelter walls for rigidity. A fabric cover is extensive between opposing portions of the box side wall and is draped over and supported by the shelter walls. The fabric cover is joined with the front and rear shelter walls and the box side wall by a surface fastening means so that the box side wall, the front and rear shelter walls and the fabric cover enclose a space for a pet. The same elements may be stored within the box base member and secured by the tension beam.