The Spanish pluperfect (aka past perfect) is used to indicate an action in the past that occurred before another action in the past. The latter can be either mentioned in the same sentence or implied. The pluperfect is a compound verb formed with the imperfect of the auxiliary verb Haber + the past participle of the main verb. The meaning of the pluperfect is equivalent to that of English verb forms such as "(we) had arrived" or "(they) had written".
To come is an irregular verb "I come" present, "I came" simple past or preterite, "I have come" present perfect, "I had come" past perfect. The past participle for this verb is "come"