I will reach Holiday Inn Beijing Airport Zone at 12 AM China time and need to go to Forbidden City.

You may walk 30 meters northwards to East Jingshun Street Bus Stop and take bus no.641 to Xibajianfang Bus Stop. Then you may walk 50 meters to Wangjing South Station to take metro line 14 to Dawang Road Station. Afterwards, you can transfer metro line 1 to Tian’an men East Station, Exit A. Upon arrival, you can find the destination directly.