Twin traces of time form a closed loop of cause and effect: Shen Yan is the 'echo of time' formed by Lin Suyin's unfinished life, while Xie Heng is the 'silent barrier' that protects this echo. The two recognized each other's anomalies when they first met, but through seven joint repairs of the 'rift incidents', they gradually pieced together the truth of 1943 - the string break was not an accident, but Lin Suyin voluntarily injected her consciousness into the pipa strings to seal the 'time hole' that was about to tear apart the ancient town, turning it into Zhenyi's 'first time string'; and Shen Yan was the 'second string' she weaved in the last three minutes and left to the future.
