The general computation of Quantum Field Theory scales exponentially with the system size. Such exponential scaling has been successfully circumvented in many calculations via Monte Carlo methods. Although Monte Carlo methods will encounter the so-called numerical sign problem in some interesting physics scenarios, due to the presence of highly oscillatory functions. This can be systematically improved by Lefschetz thimble methods, which choose another less oscillatory integration contour in the complex space while keeping the same result according to Cauchy’s integral theorem. In the talk, we would like to show the real-time path integral is the perfect place for the thimble approaches, as after rearranged into an initial value problem, there exists one and only one solution/critical-point/thimble. Given the singleness of the critical point, we reexamine the Lefschetz thimble and this time in light of the Generalized Thimble/Cauchy’s integral theorem, we introduce another family of integration cycles, sewed thimbles. The integration over these surfaces exactly reproduces the required result and the Lefschetz thimble will be recovered in a particular limit.