The Nigerian forces carry out a naval assault on Calabar after landing at Bonny Island which they use as a staging post.
They begin with heavy air bombardment.
The marine units manage to force the Biafran units back who then call for reinforcements. The 7th Battalion are requested but they say they cant come as they had lent their machine guns to another unit that was on the front line and only had bolt action rifles. Eventually they come and find they are up against Nigerian armoured cars and are beaten back.
The Biafrans then bring in some mercenaries but they to are beaten back and route and then Calabar falls to the Nigerians.
Also to note, I have made the built up area smaller that it currently is on Google Maps to reflect the fact that this was 1967 and not 2017. I imagine that the built up area would have been slightly small, but that is just an assumption.