From Plots to Endings: A Reinforced Pointer Generator for Story Ending Generation.

We introduce a new task named Story Ending Generation (SEG), which aims at generating a coherent story ending from a sequence of story plot. We propose a framework consisting of a Generator and a Reward Manager for this task. The Generator follows the pointer-generator network with coverage mechanism to deal with out-of-vocabulary (OOV) and repetitive words. Moreover, a mixed loss method is introduced to enable the Generator to produce story endings of high semantic relevance with story plots. In the Reward Manager, the reward is computed to fine-tune the Generator with policy-gradient reinforcement learning (PGRL). We conduct experiments on the recently-introduced ROCStories Corpus. We evaluate our model in both automatic evaluation and human evaluation. Experimental results show that our model exceeds the sequence-to-sequence baseline model by 15.75% and 13.57% in terms of CIDEr and consistency score respectively.