A specific physical layer network coding (PNC) scheme is proposed for the two-way relay channel. Unlike the traditional binary PNC that focuses mainly on BPSK modulation, the proposed PNC scheme is tailored for general MPSK modulation. In particular, the product of the two modulated signals is considered as a network-coded symbol. The proposed network coding operation occurs naturally in the inner or outer product of the received signal. A novel PNC-specific detection principle is then developed to estimate the network-coded symbol. Simulations show that the proposed scheme achieves almost optimal performance in terms of end-to-end bit error rate (BER), where the relay node is equipped with multiple antennas.