Takarajima 24 is a chain of internet/manga cafes with private rooms. You can put your stuff there, lock the door and then go out for the evening.
1F - 5F Kaneko Bldg., 6-9-24 Ueno, Taito-ku, Tokyo
- 125 m from Okachimachi Station Yamanote Line (JY4)Keihin-Tōhoku Line (JK29)
- 219 m from Ueno-okachimachi Station Oedo Line (E9)
- 245 m from Ueno-hirokoji Station Ginza Line (G15)