You made a promise to walk with him, but you broke the promise. The missing period of time is like a lost chapter in your life. If you don't find it back, you won't be able to synthesize the eternal frost. The missing piece of equipment will reduce the hit rate of your skills, and you won't be confident in playing. Without self-confidence, you will be knocked down by life at any time. Now you have the opportunity to return to the city and make up for the lost chapter, so as not to leave any regrets in your life.
This book is very nice