The next day?

The point-of-view principle is applicable to last week, last month, etc.  However, the past point of view does not simply add the for these.  The word last disappears and a new word (previous, preceding, or before) is used instead.

Present point of view:  yesterday, last week, last month, last year.
Past point of view:  the previous day, the previous week, the previous month, the previous year.
Also past point of view:  the day before, the week before, the month before, the year before.

(preceding may substitute for previous.)

The first of each of the sentence pairs below shows a past event from the present point of view.
The second of each pair shows a past event from the past point of view.

We went to the movies yesterday.
We had gone to the movies the day before.

I forgot to pay the gas bill last month.
I had forgotten to pay the gas bill the previous month.

CJ

Please see section 307, Practical English Usage, 2nd edition

the last wek = seven days up to now

for the last year = since twelve months ago

Anonymous wrote:

Thank you, but what gots me is the fact that the illustrated sentence can function w/o "the" when placed at the end but like you said, it has to have "the" when the phrase is placed at the beginning. Ex illustrated: I went camping to Mt. Shinaru next day. vs.  The next day, I went camping to Mt. Shinaru.

For an even more conversational fee, you could write:

The next day, went camping to Mt. Shinaru.